Delete outdated Note [Kind-checking tyvar binders for associated types]

This Note has severely bitrotted, as it has no references anywhere in the
codebase, and none of the functions that it mentions exist anymore. Let's just
delete this. While I was in town, I deleted some outdated comments from
`checkFamPatBinders` of a similar caliber.

Fixes #19008.

[ci skip]

1 files changed, 0 insertions, 18 deletions

diff --git a/compiler/GHC/Tc/Gen/HsType.hs b/compiler/GHC/Tc/Gen/HsType.hs
index 84a4553e6e..f41f99be2d 100644
--- a/compiler/GHC/Tc/Gen/HsType.hs
+++ b/compiler/GHC/Tc/Gen/HsType.hs
@@ -2819,24 +2819,6 @@ But notice that (#16322 comment:3)
   although T3 is really polymorphic-recursive too.
   Perhaps we should somehow reject that.
 
-Note [Kind-checking tyvar binders for associated types]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-When kind-checking the type-variable binders for associated
-   data/newtype decls
-   family decls
-we behave specially for type variables that are already in scope;
-that is, bound by the enclosing class decl.  This is done in
-kcLHsQTyVarBndrs:
-  * The use of tcImplicitQTKBndrs
-  * The tcLookupLocal_maybe code in kc_hs_tv
-
-See Note [Associated type tyvar names] in GHC.Core.Class and
-    Note [TyVar binders for associated decls] in GHC.Hs.Decls
-
-We must do the same for family instance decls, where the in-scope
-variables may be bound by the enclosing class instance decl.
-Hence the use of tcImplicitQTKBndrs in tcFamTyPatsAndGen.
-
 Note [Kind variable ordering for associated types]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 What should be the kind of `T` in the following example? (#15591)