gitweb: Fix links to lines in blobs when javascript-actions are enabled

The fixLinks() function adds 'js=1' to each link that does not already
have 'js' query parameter specified. This is used to signal to gitweb
that the browser can actually do javascript when these links are used.

There are two problems with the existing code:

  1. URIs with fragment and 'js' query parameter, like e.g.

        ...foo?js=0#l199

     were not recognized as having 'js' query parameter already.

  2. The 'js' query parameter, in the form of either '?js=1' or ';js=1'
     was appended at the end of URI, even if it included a fragment
     (had a hash part).  This lead to the incorrect links like this

        ...foo#l199?js=1

     instead of adding query parameter as last part of query, but
     before the fragment part, i.e.

        ...foo?js=1#l199

Signed-off-by: Peter Stuge <redacted>
Acked-by: Jakub Narebski <redacted>
Signed-off-by: Junio C Hamano <redacted>