v0.13.0

• Fixed case where inherited members could be linked to the wrong mixin (#1434)
• Added broken link detection to the search index.
• Avoid parsing markdown for ModelElements unless we're actually going to use
  the docs, speeding up generation overall by ~10% (#1417)
• Add annotations to parameter documentation (#1432)
• Change dartdoc style to use multiple independent scrolling columns (#1350)
• Add scoring for ambiguous canonicalization, and a new comment directive,
  @canonicalFor, to override its decisions (#1455)
• Add a hidden flag to drop text in docs imported from the SDK, and use this
  flag in the integration test to make that test less fragile (#1457)
• Add link to package homepage from index (#1460)
• Add [...] with a link to all one-line docs that have more information
  on the details page. (#1388)