gitweb: Highlight matched part of project name when searching projects

Use esc_html_match_hl() introduced in previous commit to escape HTML
and mark match, using span element with 'match' class.  Currently only
the 'path' part (i.e. the project name) is highlighted; match might be
on the project description.  Highlighting match in description is left
for next commit.

The code makes use of the fact that defined $search_regexp means that
there was search going on.

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gitweb/gitweb.perl

@@ -5400,7 +5400,9 @@ sub git_project_list_rows {
 			print "</td>\n";
 		}
 		print "<td>" . $cgi->a({-href => href(project=>$pr->{'path'}, action=>"summary"),
-		                        -class => "list"}, esc_html($pr->{'path'})) . "</td>\n" .
+		                        -class => "list"},
+		                       esc_html_match_hl($pr->{'path'}, $search_regexp)) .
+		      "</td>\n" .
 		      "<td>" . $cgi->a({-href => href(project=>$pr->{'path'}, action=>"summary"),
 		                        -class => "list", -title => $pr->{'descr_long'}},
 		                        esc_html($pr->{'descr'})) . "</td>\n" .