Remove dead "Comments" link from See also sidebar

Remove dead "Comments" link from See also sidebar

The comments system was removed long ago, but the link to
#comments_section remained in the See also sidebar on every page.
The target anchor no longer exists (common.xsl already has
"<!-- Comments section used to be here -->"), making this a dead link.

Remove from manualpage.xsl, synopsis.xsl, and overrideindex.xsl.
The lang/*/messages "comments" strings are left in place (harmless,
and removing them would require touching all 11 language files).

Resolves bz#70046

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1934241 13f79535-47bb-0310-9956-ffa450edef68