Escape the log tail to ensure we produce correct HTML

Dependencies

• [2] 3JBUMW3E forgot to commit a file
• [3] QWVUIGFY add link to build on tail/-reload log pages

Change contents

• replacement in src/root/plain-reload.tt at line 22
  [2.348]→[2.348:364](∅→∅)
  − [% contents -%]
  [2.348]

  [2.364]
  + [% HTML.escape(contents) -%]