hgrc.5: drop 'hgext.' prefix when talking about extensions
The first paragraph apply to all extensions, not just those in hgext.
The second paragraph can just use the simpler form to load mq.
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init
$ echo 'base' > base
$ hg ci -Ambase
adding base
$ hg qnew -mmqbase mqbase
$ hg qsave
$ hg qrestore 2
restoring status: hg patches saved state