Update playbooks_tags.rst (#75472)

##### SUMMARY
When I used this example it complains with:

ERROR! The tasks/main.yml file for role 'myrole' must contain a list of tasks

The error appears to be in 'ansible/roles/myrole/tasks/main.yml': line 2, column 1, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

---
tasks:
^ here

Removing "tasks:" fixes it.


##### ISSUE TYPE
- Docs Pull Request

+label: docsite_pr

docs/docsite/rst/user_guide/playbooks_tags.rst

@@ -128,7 +128,6 @@ If you want to apply a tag to many, but not all, of the tasks in your play, use
 .. code-block:: yaml
 
    # myrole/tasks/main.yml
-   tasks:
    - name: ntp tasks
      tags: ntp
      block: