Clarify pygrep behaviour when matching at the end of a string

[nijel]

It is not obvious that newline is included in the matched line and it took me quite some time to figure out.

[asottile]

this is already specified as a python regex so this behavior should be expected. also $ will match already without the new line being part of the pattern

[nijel]

Hmm, it indeed does match for this simple case, but it doesn't work like that for all regexp. Sorry for providing a bad example.

What I wanted to catch:

* This is a correct changelog entry with a stop.
* This is an invalid entry

This doesn't work as expected because [^.] is consumed by \n:

  - id: rst-bullet-stop
    name: Changes end with a stop
    description: Bullet list in changes should end with a stop.
    files: docs/changes\.rst
    entry: ^ *\* .*[^.]$
    language: pygrep

This does work:

  - id: rst-bullet-stop
    name: Changes end with a stop
    description: Bullet list in changes should end with a stop.
    files: docs/changes\.rst
    entry: ^ *\* .*[^.]\n$
    language: pygrep

[asottile]

yeah that's just how regex works. nothing special here

[asottile]

your character class is too greedy