message: Document docs.rs metadata on the 'about' page.
diff: </tbody>
  </table>
  + <h4>Metadata for custom builds</h4>
  +
  + <p>You can customize docs.rs builds by defining <code>[package.metadata.docs.rs]</code> table in your crates' `Cargo.toml`.</p>
  +
  + <p>An example metadata:</p>
  +
  + <pre><code>[package]
  + name = "test"
  +
  + [package.metadata.docs.rs]
  + features = [ "feature1", "feature2" ]
  + all-features = true
  + no-default-features = true
  + default-target = "x86_64-unknown-linux-gnu"
  + rustc-args = [ "--example-rustc-arg" ]
  + rustdoc-args = [ "--example-rustdoc-arg" ]
  + dependencies = [ "example-system-dependency" ]</pre></code>
  +
  <h4>Version</h4>
  <p>Currently running Docs.rs version is: <strong>{{cratesfyi_version}}</strong>
  