comments: don't open comment form on page load for comments on line 0

Data attributes have magic parsing of strings so '0' becomes 0 which is false.

Further, 0 == '' in JavaScript, so we have to use !== '' to catch empty strings.

kallithea/public/js/base.js

@@ -528,7 +528,7 b' function move_comments($anchorcomments) '
         var line_no = $anchorcomment.data('line_no');
         if ($comment_div[0]) {
             $comment_div.append($anchorcomment.children());
-            if (f_path && line_no) {
+            if (f_path && line_no !== '') {
                 _comment_div_append_add($comment_div, f_path, line_no);
             } else {
                 _comment_div_append_form($comment_div, f_path, line_no);