Minor markup tweaks (Sy instead of Nm).

@@ -391,61 +391,61 @@
 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
+.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 Nm Committed
+.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
-.Nm Standard
+.Sy Standard
 interfaces.
-.It Nm Uncommitted
+.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
-.Nm Uncommitted
+.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 Nm Volatile
+.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 Nm Not-an-Interface
+.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 Nm Private
+.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 Nm Obsolete
+.It Sy Obsolete
 The interface is not intended for use in new projects or programs, and may
 be removed at a future date.  The
-.Nm Obsolete
+.Sy Obsolete
 word is a modifier that can
 be applied to other commitment levels. For example an
-.Nm Obsolete Committed
+.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

@@ -452,43 +452,43 @@
 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
+.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 Nm Unsafe
+.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 Nm MT-Safe
+.It Sy MT-Safe
 Indicates that the interface is not only safe for concurrent use, but is
 designed for such use.  For example, a
-.Nm Safe
+.Sy Safe
 interface may make use of a global lock to provide safety, but at reduced
 internal concurrency, whereas an
-.Nm MT-Safe
+.Sy MT-Safe
 interface will be designed to be efficient even when used concurrently.
-.It Nm Async-Signal-Safe
+.It Sy Async-Signal-Safe
 Indicates that the library is safe for use within a signal handler.  An
-.Nm MT-Safe
+.Sy MT-Safe
 interface can be made
-.Nm Async-Signal-Safe
+.Sy Async-Signal-Safe
 by ensuring that it blocks signals when acquiring locks.
-.It Nm Safe with Exections
+.It Sy Safe with Exections
 As for
-.Nm Safe
+.Sy Safe
 but with specific exceptions noted.
-.It Nm MT-Safe with Exections
+.It Sy MT-Safe with Exections
 As for
-.Nm MT-Safe
+.Sy MT-Safe
 but with specific exceptions noted.
 .El
 .It Em SECURITY
 Documents any security precautions that operators should consider.
 .It Em SEE ALSO