Add vim syntax highlighting support to the send-pr(1) utility.

PR:		35333
Submitted by:	Hendrik Scholz <hendrik@scholz.net>

gnu/usr.bin/send-pr/send-pr.sh

@@ -300,6 +300,8 @@ else
     for file in $TEMP $REF ; do
       cat  > $file << '__EOF__'
 SEND-PR: -*- send-pr -*-
+SEND-PR: vim: syntax=send-pr (needed for vim syntax highlighting)
+SEND-PR:
 SEND-PR: Lines starting with `SEND-PR' will be removed automatically, as
 SEND-PR: will all comments (text enclosed in `<' and `>').
 SEND-PR: