message: [website] Fixes broken URLs
diff: <h3>What graph algorithms are implemented in sigma.js?</h3>
  <p>
  None in sigma.js, but graphology has a lot, from
  - <a href="https://github.com/graphology/graphology-layout-forceatlas2">ForceAtlas2 layout</a> to
  - <a href="https://github.com/graphology/graphology-metrics">various metrics</a> or even
  - <a href="https://github.com/graphology/graphology-communities-louvain">community detection</a>.
  + <a href="https://graphology.github.io/standard-library/layout-forceatlas2.html">ForceAtlas2 layout</a> to
  + <a href="https://graphology.github.io/standard-library/metrics.html">various metrics</a> or even
  + <a href="https://graphology.github.io/standard-library/communities-louvain.html">community detection</a>.
  <strong>
  You can see an overview
  - <a href="https://graphology.github.io/standard-library.html">in the documentation</a>.
  + <a href="https://graphology.github.io/standard-library/">in the documentation</a>.
  </strong>
  </p>
  </li>
  