Add comment

[CI skip]
Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/static/loader-bootstrap.js

@@ -6,6 +6,7 @@ if (window.location.hash && window.location.hash === '#_=_') {
     window.location.hash = '';
 }
 
+// Loading indicator handler
 function increaseLoading(sel) {
     if (loading === 0) {
         $(sel).show();