Add links for context in API design. Include link to the iterators TC39 proposal and the API review doc.
Add links for context in API design.
Include link to the iterators TC39 proposal and the API review doc.

RELNOTES: Add API design context to goog.collections.iters
PiperOrigin-RevId: 430362203
Change-Id: Ie19b4ebf77e9547f9e5bf4ad96b90fdb713c1f5d

google/closure-library,google/closure-library,google/closure-library,google/closure-library,google/closure-library