hgweb: fix lack of "bookmarks" link in "/file" page of "paper" style
This patch also fixes same problem of "coal" style, because it re-uses
"filerevision.tmpl" of "paper" style.
"gitweb" and "monoblue" styles don't have such problems.
"spartan" style doesn't have "bookmarks" page definition itself.
Minimal hgk check
$ echo "[extensions]" >> $HGRCPATH
$ echo "hgk=" >> $HGRCPATH
$ hg init repo
$ cd repo
$ echo a > a
$ hg ci -Am adda
adding a
$ hg debug-cat-file commit 0
tree a0c8bcbbb45c
parent 000000000000
author test 0 0
revision 0
branch default
phase draft
adda
$ cd ..