Minor markup tweaks (Sy instead of Nm).

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  should support at least UTF-8 in addition to ASCII.
  .It Em INTERFACE STABILITY
  Indicates the level of commitment to the interface. Interfaces can be described
  with in the following ways:
  .Bl -tag -width Ds
! .It Nm Standard
  Indicates that the interface is defined by one or more standards bodies.
  Generally, changes to the interface will be carefully managed to conform
  to the relevant standards.  These interfaces are generally the most suitable
  for use in portable programs.
! .It Nm Committed
  Indicates that the interface is intended to be preserved for the long-haul, and
  will rarely, if ever change, and never without notification (barring
  extraordinary and extenuating circumstances). These interfaces are
  preferred over other interfaces with the exeception of
! .Nm Standard
  interfaces.
! .It Nm Uncommitted
  Indicates that the interface may change.  Generally, changes to these interfaces
  should be infrequent, and some effort will be made to address compatibility
  considerations when changing or removing such interfaces.  However, there is
  no firm commitment to the preservation of the interface.  Most often this
  is applied to interfaces where operational experience with the interface
  is still limited and some need to change may be anticipated.
  .Pp
  Consumers should expect to revalidate any
! .Nm Uncommitted
  interfaces when crossing release boundaries.  Products intended for
  use on many releases or intended to support compatibility with future
  releases should avoid these interfaces.
! .It Nm Volatile
  The interface can change at any time for any reason. Often this relates to
  interfaces that are part of external software components that are still evolving
  rapidly.  Consumers should not expect that the interface (either binary or
  source level) will be unchanged from one release to the next.
! .It Nm Not-an-Interface
  Describes something that is specifically not intended for programmatic
  consumption.  For example, specific human-readable output, or the layout
  of graphical items on a user interface, may be described this way.  Generally
  programmatic alternatives to these will be available, and should be used
  when programmatic consumption is needed.
! .It Nm Private
  This is an internal interface.  Generally these interfaces should only be
  used within the project, and should not be used by other programs or modules.
  The interface can and will change without notice as the project needs, at
  any time.
  .Pp
  Most often, Private interfaces will lack any documentation whatsoever, and
  generally any undocumented interface can be assumed to be Private.
! .It Nm Obsolete
  The interface is not intended for use in new projects or programs, and may
  be removed at a future date.  The
! .Nm Obsolete
  word is a modifier that can
  be applied to other commitment levels. For example an
! .Nm Obsolete Committed
  interface is unlikely to be removed or changed, but nonetheless new use
  is discouraged (perhaps a better newer alternative is present).
  .El
  .It Em MT-LEVEL
  This section describes considerations for the interface when used within
--- 391,451 ----
  should support at least UTF-8 in addition to ASCII.
  .It Em INTERFACE STABILITY
  Indicates the level of commitment to the interface. Interfaces can be described
  with in the following ways:
  .Bl -tag -width Ds
! .It Sy Standard
  Indicates that the interface is defined by one or more standards bodies.
  Generally, changes to the interface will be carefully managed to conform
  to the relevant standards.  These interfaces are generally the most suitable
  for use in portable programs.
! .It Sy Committed
  Indicates that the interface is intended to be preserved for the long-haul, and
  will rarely, if ever change, and never without notification (barring
  extraordinary and extenuating circumstances). These interfaces are
  preferred over other interfaces with the exeception of
! .Sy Standard
  interfaces.
! .It Sy Uncommitted
  Indicates that the interface may change.  Generally, changes to these interfaces
  should be infrequent, and some effort will be made to address compatibility
  considerations when changing or removing such interfaces.  However, there is
  no firm commitment to the preservation of the interface.  Most often this
  is applied to interfaces where operational experience with the interface
  is still limited and some need to change may be anticipated.
  .Pp
  Consumers should expect to revalidate any
! .Sy Uncommitted
  interfaces when crossing release boundaries.  Products intended for
  use on many releases or intended to support compatibility with future
  releases should avoid these interfaces.
! .It Sy Volatile
  The interface can change at any time for any reason. Often this relates to
  interfaces that are part of external software components that are still evolving
  rapidly.  Consumers should not expect that the interface (either binary or
  source level) will be unchanged from one release to the next.
! .It Sy Not-an-Interface
  Describes something that is specifically not intended for programmatic
  consumption.  For example, specific human-readable output, or the layout
  of graphical items on a user interface, may be described this way.  Generally
  programmatic alternatives to these will be available, and should be used
  when programmatic consumption is needed.
! .It Sy Private
  This is an internal interface.  Generally these interfaces should only be
  used within the project, and should not be used by other programs or modules.
  The interface can and will change without notice as the project needs, at
  any time.
  .Pp
  Most often, Private interfaces will lack any documentation whatsoever, and
  generally any undocumented interface can be assumed to be Private.
! .It Sy Obsolete
  The interface is not intended for use in new projects or programs, and may
  be removed at a future date.  The
! .Sy Obsolete
  word is a modifier that can
  be applied to other commitment levels. For example an
! .Sy Obsolete Committed
  interface is unlikely to be removed or changed, but nonetheless new use
  is discouraged (perhaps a better newer alternative is present).
  .El
  .It Em MT-LEVEL
  This section describes considerations for the interface when used within
*** 452,494 ****
  programs that use multiple threads.  More discussion of these considerations
  is made in the MT-Level section of
  .Xr attributes 5 .
  The interface can be described in the following ways.
  .Bl -tag -width Ds
! .It Nm Safe
  Indicates the interface is safe for use within multiple threads.  There
  may be additional caveats that apply, in which case those will be
  described.  Note that some interfaces have semantics which may affect
  other threads, but these should be an intrinsic part of the interface
  rather than an unexpected side effect.  For example, closing a file in
  one thread will cause that file to be closed in all threads.
! .It Nm Unsafe
  Indicates the interface is unsuitable for concurrent use within multiple
  threads.  A threaded application may still make use of the interface, but
  will be required to provide external synchronization means to ensure that
  only a single thread calls the interface at a time.
! .It Nm MT-Safe
  Indicates that the interface is not only safe for concurrent use, but is
  designed for such use.  For example, a
! .Nm Safe
  interface may make use of a global lock to provide safety, but at reduced
  internal concurrency, whereas an
! .Nm MT-Safe
  interface will be designed to be efficient even when used concurrently.
! .It Nm Async-Signal-Safe
  Indicates that the library is safe for use within a signal handler.  An
! .Nm MT-Safe
  interface can be made
! .Nm Async-Signal-Safe
  by ensuring that it blocks signals when acquiring locks.
! .It Nm Safe with Exections
  As for
! .Nm Safe
  but with specific exceptions noted.
! .It Nm MT-Safe with Exections
  As for
! .Nm MT-Safe
  but with specific exceptions noted.
  .El
  .It Em SECURITY
  Documents any security precautions that operators should consider.
  .It Em SEE ALSO
--- 452,494 ----
  programs that use multiple threads.  More discussion of these considerations
  is made in the MT-Level section of
  .Xr attributes 5 .
  The interface can be described in the following ways.
  .Bl -tag -width Ds
! .It Sy Safe
  Indicates the interface is safe for use within multiple threads.  There
  may be additional caveats that apply, in which case those will be
  described.  Note that some interfaces have semantics which may affect
  other threads, but these should be an intrinsic part of the interface
  rather than an unexpected side effect.  For example, closing a file in
  one thread will cause that file to be closed in all threads.
! .It Sy Unsafe
  Indicates the interface is unsuitable for concurrent use within multiple
  threads.  A threaded application may still make use of the interface, but
  will be required to provide external synchronization means to ensure that
  only a single thread calls the interface at a time.
! .It Sy MT-Safe
  Indicates that the interface is not only safe for concurrent use, but is
  designed for such use.  For example, a
! .Sy Safe
  interface may make use of a global lock to provide safety, but at reduced
  internal concurrency, whereas an
! .Sy MT-Safe
  interface will be designed to be efficient even when used concurrently.
! .It Sy Async-Signal-Safe
  Indicates that the library is safe for use within a signal handler.  An
! .Sy MT-Safe
  interface can be made
! .Sy Async-Signal-Safe
  by ensuring that it blocks signals when acquiring locks.
! .It Sy Safe with Exections
  As for
! .Sy Safe
  but with specific exceptions noted.
! .It Sy MT-Safe with Exections
  As for
! .Sy MT-Safe
  but with specific exceptions noted.
  .El
  .It Em SECURITY
  Documents any security precautions that operators should consider.
  .It Em SEE ALSO