Relative links have 2 advantages :
* They're not marked as external links
* When on a specific doc version, the link point to the same version.
PR Close#50080
This update describes the content authoring and revision process in sufficient detail for technical and non-technical contributors to the angular.io documentation.
PR Close#47381
Adds suggestions for how to resolve the most common messages produced by the documentation linter.
Adds links to the Proselint and other style tests to the new documentation.
Updates pullapprove and navigation.
PR Close#47019
