message: Update src/web/mod.rs
diff: @@ -163,6 +163,8 @@ impl Handler for MainHandler {
  }
  }
  + // This is kind of a mess.
  + //
  // Some versions of rustdoc in 2018 did not respect the shared static root
  // (--static-root-path) and so emitted HTML that linked to shared static files via a local
  // path. For instance, `<script src="../main-20181217-1.33.0-nightly-adbfec229.js">` instead
  