Fix typechecking of (syntax ...) expressions

The type is
  (Syntaxof the-type-of-the-result-of-syntax-e), not
  (Syntaxof the-type-of-the-result-of-syntax->datum)

Closes PR 14561
Adjust types for stx-map and syntax->list

These types need to be adjusted to match the types that
are now produced for syntax datums due to the previous
commit.