gitweb: handle "patch" query parameter in filelog view

As for paper style, in f36dc643ffdc, we display "diff" data as an additional
row in the table of revision entries for the gitweb template.
Also, as these additional diff rows have a white background, they may be
confused with log entry rows ("age", "author", "description", "links") of even
parity (parity0 also have a white background). So we disable parity colors for
log entry rows when diff is displayed and fix the color to the
"dark" parity (i.e. parity1 #f6f6f0) so that it's always distinguishable from

mercurial/templates/gitweb/map

@@ -282,7 +282,7 b" shortlogentry = '"
     </td>
   </tr>'
 filelogentry = '
-  <tr class="parity{parity}">
+  <tr class="parity{if(patch, '1', '{parity}')}">
     <td class="age"><i class="age">{date|rfc822date}</i></td>
     <td><i>{author|person}</i></td>
     <td>
@@ -297,7 +297,8 b" filelogentry = '"
       <a href="{url|urlescape}annotate/{node|short}/{file|urlescape}{sessionvars%urlparameter}">annotate</a>
       {rename%filelogrename}
     </td>
-  </tr>'
+  </tr>
+  {if(patch, '<tr><td colspan="4">{diff}</td></tr>')}'
 archiveentry = ' | <a href="{url|urlescape}archive/{symrev}{extension}{ifeq(path,'/','',path|urlescape)}">{type|escape}</a> '
 indexentry = '
   <tr class="parity{parity}">