rpc.5: ffix

* Remove nop argument from HP macros.
* Remove nop DT macro.
* Replace LP macro with more commonly-used PP macro.

The above do not change the output whatsoever (confirmed with -Z).

* Use .I macro instead of font escapes, obtaining italic correction.

To see the above distinction, use -Tps, -Tpdf, or similar before and
after the change.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man5/rpc.5

@@ -16,25 +16,26 @@ The
 file contains user readable names that
 can be used in place of RPC program numbers.
 Each line has the following information:
-.HP 10
+.HP
 name of server for the RPC program
 .br
 .ns
-.HP 10
+.HP
 RPC program number
 .br
 .ns
-.HP 10
+.HP
 aliases
-.LP
+.PP
 Items are separated by any number of blanks and/or
 tab characters.
 A \(aq#\(aq indicates the beginning of a comment; characters from
 the \(aq#\(aq to the end of the line are not interpreted by routines
 which search the file.
-.LP
-Here is an example of the \fI/etc/rpc\fP file from the Sun RPC Source
-distribution.
+.PP
+Here is an example of the
+.I /etc/rpc
+file from the Sun RPC Source distribution.
 .ft CW
 .nf
 #
@@ -72,7 +73,6 @@ nsed            100038
 nsemntd         100039
 .fi
 .ft
-.DT
 .SH FILES
 .TP
 .I /etc/rpc