<!--- 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 -->

section: defaults
      display_ok_hosts:
        name: Show 'ok' hosts
        description: "Toggle to control displaying 'ok' task/host results in a task"
        type: bool
        default: yes
        env:
          - name: ANSIBLE_DISPLAY_OK_HOSTS
        ini:
          - key: display_ok_hosts
            section: defaults
        version_added: '2.7'
      display_failed_stderr:
        name: Use STDERR for failed and unreachable tasks
        description: "Toggle to control whether failed and unreachable tasks are displayed to STDERR (vs. STDOUT)"
        type: bool
        default: no
        env:
          - name: ANSIBLE_DISPLAY_FAILED_STDERR
        ini:
          - key: display_failed_stderr
            section: defaults
        version_added: '2.7'
      show_custom_stats:
        name: Show custom stats
        description: 'This adds the custom stats set via the set_stats plugin to the play recap'
        type: bool
        default: no
        env:
          - name: ANSIBLE_SHOW_CUSTOM_STATS