add link to build on tail/-reload log pages

Dependencies

• [2] 3JBUMW3E forgot to commit a file
• [3] RGRBQI2F show all related jobset/job links in navbar for the tail/-reload logs

Change contents

• replacement in src/root/plain-reload.tt at line 8
  [2.63]→[2.63:93](∅→∅)
  − <h2>Last 50 lines of log</h2>
  [2.63]

  [2.93]
  + <h2>Last 50 log lines of [% INCLUDE renderFullJobNameOfBuild %] build <a href="[% c.uri_for('/build' build.id) %]">[% build.id %]</a>[%IF step %] step [% step.stepnr %][% END %]</h2>