add mastodon link for verification

tools/page_shares.py

@@ -9,6 +9,7 @@ HEAD_EMBED = """
 <li><a href="/feed.xml">rss</a></li>
 <li><a href="/articles/mjestečko.html">about</a></li>
 <li><a href="https://modarchive.org/index.php?request=view_artist_modules&query=96070">tracks</a></li>
+<li><a rel="me" href="https://poto.cafe/@veclavtalica">mastodon</a></li>
 </ul>
 </nav>