lint for generic parameters in comments

[harryterkelsen]

GOOD:

T identity<T>(T x) => x;

BAD:

dynamic/*=T*/ identity/*<T>*/(dynamic/*=T*/ x) => x;

[alexeieleusis]

With a quickfix!

[srawlins]

This syntax is going away very soon. Just FYI. #28796

[bwilkerson]

We already have a hint for this.