<!--- Verify first that your feature was not already discussed on GitHub -->
<!--- Complete *all* sections as described, this form is processed automatically -->

##### SUMMARY
<!--- Describe the new feature/improvement briefly below -->
I'd like to see variables added to ansible_failed_task which represent the filename and line of the task that failed.  This information is available inside the JUnit callback module already, but would be helpful to expose for better information in a rescue block notice.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
ansible_failed_task

##### ADDITIONAL INFORMATION
<!--- Describe how the feature would be used, why it is needed and what it would solve -->
The name of the task is nice, but in large projects may not be specific enough to hunt though and find the file/line to troubleshoot.  This is even worse if the names of tasks aren't unique.  This provide something like a slack task in a rescue block the ability to inform where the fault is possible to have come from.

<!--- Paste example playbooks or commands between quotes below -->
```yaml

```

<!--- HINT: You can also paste gist.github.com links for larger files -->

import json
import os
import sys
import warnings
from copy import deepcopy
from ansible import constants as C
from ansible.module_utils.common._collections_compat import MutableMapping
from ansible.module_utils.six import PY3
from ansible.module_utils._text import to_text
from ansible.parsing.ajson import AnsibleJSONEncoder
from ansible.plugins import AnsiblePlugin, get_plugin_class
from ansible.utils.color import stringc
from ansible.utils.display import Display
from ansible.vars.clean import strip_internal_keys, module_response_deepcopy
if PY3:
    
    
    from collections import OrderedDict
else:
    OrderedDict = None
global_display = Display()
__all__ = ["CallbackBase"]
_DEBUG_ALLOWED_KEYS = frozenset(('msg', 'exception', 'warnings', 'deprecations'))
class CallbackBase(AnsiblePlugin):
    '''
    This is a base ansible callback class that does nothing. New callbacks should
    use this class as a base and override any callback methods they wish to execute
    custom actions.
    '''
    def __init__(self, display=None, options=None):