haskell-align-imports is confused by the word "instance" in comments

Example code:
```
-- instance

import A
import qualified B
```
fails to align. But a typo in `instance` above makes it succeed. i.e: it's probably being confused by keywords in comments.

Reproduce the example with haskell-align-imports, then inspect the command's parsing and comment-handling logic. The fix is complete when a comment containing "instance" no longer changes the alignment result for the imports shown.

Written by the indexing model from the issue text.