Fix #1050 by filtering out invisible AppTy arguments

This makes the `synifyType` case for `AppTy` more intelligent by
taking into consideration the visibilities of each `AppTy` argument
and filtering out any invisible arguments, as they aren't intended
to be displayed in the source code. (See #1050 for an example of what
can happen if you fail to filter these out.)

Along the way, I noticed that a special `synifyType` case for
`AppTy t1 (CoercionTy {})` could be consolidated with the case below
it, so I took the opportunity to tidy this up.

0 files changed, 0 insertions, 0 deletions