62337 [Material] Add support for high contrast theming to Material apps (cla: yes, f: material design, framework, waiting for tree to go green)

62338 Replace mistaken dartdoc [Foo..bar] references with [Foo.bar] (cla: yes, f: material design, framework, waiting for tree to go green)

62367 Make dartdoc warnings fatal (& cleanup of warnings) (a: accessibility, a: internationalization, a: tests, cla: yes, f: cupertino, f: material design, framework, team, waiting for tree to go green)

62421 Export Material curves in the Material lib (cla: yes, f: material design, framework)

62431 Revert “Export Material curves in the Material lib” (cla: yes, f: material design, framework)