Bad autocomplete in comments

I have recently been receiving autocomplete when pressing enter at the end of a sentence in a comment:

```haskell
-- foo is a number.
foo = 1
```

If my cursor is at the full stop after "number", and I press enter, then I normally get `{-# ANN annotation #-}` inserted, or some random Core variable.

It would be good to only provide autocomplete outside of comments imo...