Improve Autocompletion of pragmas within instance declarations #3356
Description
Take this for example:
The completion only occurs if it happens between two {-# #-}, and if I select the completion, this is the result:
This is invalid code. Would be better if we did not introduce the second #-}.
In LANGUAGE pragmas at the very beginning of a file, this does not happen, so I presume this requires just a little bit of fine-tuning of the existing code and adding a test-case.