##### SUMMARY
I think the `regex_replace` jinja filter should support `multiline` as the `regex_search` do.
Or maybe use a `flags` parameter to support any `re` flag.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
- `lib/ansible/plugins/filter/core.py`

##### ADDITIONAL INFORMATION
Example: comment a multiline variable.
```yaml
  val: "{{ val | regex_replace('^', '#', multiline=True) }}"
```
comment_styles = {
        'plain': {
            'decoration': '# '
        },
        'erlang': {
            'decoration': '% '
        },
        'c': {
            'decoration': '// '
        },
        'cblock': {
            'beginning': '/*',
            'decoration': ' * ',
            'end': ' */'
        },