Drop the data-fam-instance "Kind" panel entry entirely

Drop the data-fam-instance "Kind" panel entry entirely

The previous text was wrong on two counts: it labelled the row "Kind"
even though it wasn't showing any kind, and it called the rhs a
"synthetic GHC-internal data constructor" — but the user *did* write
the data constructor (`CrateInt Int`, etc.); the only synthetic part
is the R: TyCon GHC uses internally to represent the instance.

We don't extract data constructors into the schema, so we have
nothing useful to show on the rhs side for data fam-instances. Just
omit the row.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>