more copy-editting from Josh

@@ -74,67 +74,67 @@
 .Fa source ,
 which may be
 .Dv NULL
 if this arena does not import from another.
 When calling
-.Fn vmem_create
+.Fn vmem_create ,
 .Fa afunc
-is an
-.Vt vmem_alloc_t
+is a
+.Vt vmem_alloc_t ,
 a function taking three parameters and returning a pointer to
 .Vt void
 (the imported space):
 .Bl -tag -width Ds
 .It Fa "vmem_t *"
 The source arena from which we'll import.  The
 .Fa source
 argument to
 .Fn vmem_create .
 .It Fa size_t
-The size to import
+The size to import.
 .It Fa int
 The
 .Fa vmflag
 argument used for the import.
 .El
 .Pp
 When calling
-.Fn vmem_xcreate
+.Fn vmem_xcreate ,
 .Fa afunc
-is an
-.Vt vmem_ximport_t
+is a
+.Vt vmem_ximport_t ,
 a function taking four parameters and returning a pointer to
 .Vt void
 (the imported space):
 .Bl -tag -width Ds
 .It Fa "vmem_t *"
 The source arena from which we'll import.  The
 .Fa source
 argument to
 .Fn vmem_xcreate .
 .It Fa "size_t *"
-The size of the import,
+The size of the import.
 .Fa afunc
 may
 .Em increase
 this size if that is desirable, but must never decrease it.
 .It Fa size_t
 The desired alignment of the imported space.
 .It Fa int
-the
+The
 .Fa vmflag
 argument used for the import.
 .El
 .It Fa ffunc
 A function which is called to return spans to
 .Fa source ,
 which may be
 .Dv NULL
 if this arena does not import from another.
 This is a
-.Vt vmem_free_t
-a function taking three parametes and returning void:
+.Vt vmem_free_t ,
+a function taking three parameters and returning void:
 .Bl -tag -width Ds
 .It Fa "vmem_t"
 The arena to which space is being returned.  The
 .Fa source
 argument to