##### 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) }}"
```
'checksum': checksum_s,
            
            'password_hash': get_encrypted_password,
            'hash': get_hash,
            
            'regex_replace': regex_replace,
            'regex_escape': regex_escape,
            'regex_search': regex_search,
            'regex_findall': regex_findall,
            
            'ternary': ternary,
            
            'random': rand,
            'shuffle': randomize_list,
            
            'mandatory': mandatory,
            
            'comment': comment,
            
            'type_debug': lambda o: o.__class__.__name__,
            
            'combine': combine,
            'extract': extract,
            'flatten': flatten,
            'dict2items': dict_to_list_of_dict_key_value_elements,
            'items2dict': list_of_dict_key_value_elements_to_dict,
            'subelements': subelements,
        }