Enhance kind inference for data family instances

This commit improves kind inference for data family instances by kind-checking
the constructors, for H98 and newtype declarations (ONLY), as well as
kind-checking the result kind signature (when using GADT syntax).
This fixes #25611.

Typechecker changes:
In `tcDataFamInstHeader`, we now kind-check the constructors using
`kcConDecls`, for H98-style decls and newtype decls ONLY.
See Note [Kind inference for data family instances].

Testsuite changes:
  - The T25611{a,b,c,d} tests test the new kind inference implementation.
    - a,b: infer result kind from constructors (H98 case)
    - c: renamed version of test UnliftedNewtypesUnassociatedFamilyFail,
      which now passes
    - d: GADT case, checking that we don't infer overly rigid kinds when
         kind-checking the constructors in data family instances.
 - DataInstanceKindsDefaults tests defaulting data instance kinds
   without UnliftedNewtypes or UnliftedDatatypes, as outlined in
   Note [Defaulting result kind of newtype/data family instance].

Also a few notes are updated to reflect the changes.

Co-authored-by: default avatarSimon Peyton Jones <simon.peytonjones@gmail.com>