* make certain props in feature links nullable
* update openapi models
* update TS type def for FeatureLink
* remove information and http_error_code required
* Use LinkPreview instead of LinkPreviewBase
* information set to optional
* Update stale feature links
* Support parse LINK_TYPE_GITHUB_ISSUE
* Support parse LINK_TYPE_GITHUB_MARKDOWN
* Fix mypy complains
* Improve markdown title parse
* Add comments
* Use cloud task to update feature links information
* Delay 10 seconds for second feature links request
* Add TODO
* Fix feature_links edge cases
* Add basic FeatureLinksAPI
* Add feature-link to enhance autolink and normal url in feature detail page
* Add tooltip to enhanceChromeStatusLink, polish styles
* Make featureLinks non blocking request
* Add closedTimestamp in enhanceChromeStatusLink
* Remove placeholder function
* Add back white-space: pre-wrap and fix CSS
* Use gray color badge for closed issue
* Rename fallback and change it to a lit-html object
* Move feature link summary into tooltip
* Support custom text in enhanceUrl