gitweb: Describe (possible) gitweb.js minification in gitweb/README

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

gitweb/README

@@ -95,7 +95,8 @@ You can specify the following configuration variables when building GIT:
  * GITWEB_JS
    Points to the localtion where you put gitweb.js on your web server
    (or to be more generic URI of JavaScript code used by gitweb).
-   Relative to base URI of gitweb.  [Default: gitweb.js]
+   Relative to base URI of gitweb.  [Default: gitweb.js (or gitweb.min.js
+   if JSMIN build variable is defined / JavaScript minifier is used)]
  * GITWEB_CONFIG
    This Perl file will be loaded using 'do' and can be used to override any
    of the options above as well as some other options -- see the "Runtime