manuals: Fix errors in .2 pages

These were reported by `mandoc -T lint ...` as errors.

fhlink.2, fhreadlink.2: remove unneeded block closing.

getfh.2, procctl.2: add necessary block closing.

ptrace.2: -width only takes one argument.

swapon.2: <sys/vmparam.h> and <vm/swap_pager.h> weren't being displayed,
    because .It is for a list item whereas .In is for included files.
    Also, we want a blank line between <sys/ > headers and the other
    one.

Signed-off-by:	Graham Percival <gperciva@tarsnap.com>
PR:		281597
Reviewed by:	mhorne
Sponsored by:	Tarsnap Backup Inc.

lib/libsys/fhlink.2

@@ -38,7 +38,6 @@
 .Fn fhlink "fhandle_t *fhp" "const char *to"
 .Ft int
 .Fn fhlinkat "fhandle_t *fhp" "int tofd" "const char *to"
-.Fc
 .Sh DESCRIPTION
 The
 .Fn fhlink

lib/libsys/fhreadlink.2

@@ -36,7 +36,6 @@
 .In sys/mount.h
 .Ft int
 .Fn fhreadlink "fhandle_t *fhp" "char *buf" "size_t bufsize"
-.Fc
 .Sh DESCRIPTION
 The
 .Fn fhreadlink
@@ -86,7 +85,6 @@ The file handle
 .Fa fhp
 is no longer valid
 .El
-.El
 .Sh SEE ALSO
 .Xr fhstat 2 ,
 .Xr fhlink 2 ,

lib/libsys/getfh.2

@@ -212,6 +212,7 @@ argument is not an absolute path and
 is neither
 .Dv AT_FDCWD
 nor a file descriptor associated with a directory.
+.El
 .Sh SEE ALSO
 .Xr fhopen 2 ,
 .Xr open 2 ,

lib/libsys/procctl.2

@@ -712,6 +712,7 @@ following statuses:
 The status is or-ed with the
 .Va PROC_KPTI_STATUS_ACTIVE
 in case KPTI is active for the current address space of the process.
+.El
 .Sh NOTES
 Disabling tracing on a process should not be considered a security
 feature, as it is bypassable both by the kernel and privileged processes,

lib/libsys/ptrace.2

@@ -830,7 +830,7 @@ value.
 If the system call completed in an unusual fashion,
 .Va sr_error
 is set to a negative value:
-.Bl -tag -width Dv EJUSTRETURN -compact
+.Bl -tag -width EJUSTRETURN -compact
 .It Dv ERESTART
 System call will be restarted.
 .It Dv EJUSTRETURN

lib/libsys/swapon.2

@@ -34,8 +34,9 @@
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
-.It vm/vm_param.h
-.It vm/swap_pager.h
+.In vm/vm_param.h
+.In vm/swap_pager.h
+.Pp
 .In unistd.h
 .Ft int
 .Fn swapon "const char *special"