gerrit: Output space in commentlink "commit" before the link

Follows-up e69e223552.

Use 'html' instead of 'link' since there are two matches. This
way we can restore the the first match outside the link (where
it belongs).

This is pretty straight forward considering commentlink.html
just defaults to comment.link in an anchor tag.

google/gerrit/GerritConfigProvider.java:

	String link = cfg.getString("commentlink", name, "link");
	String html = cfg.getString("commentlink", name, "html");
	if (html == null || html.isEmpty()) {
	html = "<a href=\"" + link + "\">$&</a>";
	}
	links.add(new RegexFindReplace(match, html));

Bug: T52711
Change-Id: I6a0e149592503e37cfccb4ea46b0226f7e8aff72