Update playbooks_roles.rst

Fixes https://github.com/ansible/ansible/issues/7241
Removing hard coded link and replacing with reference
Fix the synopsis in ansible-pull man page.
Update playbooks_variables.rst

There is some kind of duplicated content with http://docs.ansible.com/faq.html#how-do-i-loop-over-a-list-of-hosts-in-a-group-inside-of-a-template and this gotcha isn't listed here.
Update developing_modules.rst
Ignore compiled Python for documentation.

When running `ansible-doc --list` a lot of errors are
generated when `ansible-doc` tries to find documentation
strings in `.pyc` files.
Update playbooks_intro.rst

Small punctuation/grammar fix.
Merge pull request #9402 from mscherer/fix_man_ansible_pull

Fix the synopsis in ansible-pull man page.
Merge pull request #9410 from dannyroberts/patch-1

Update developing_modules.rst
Merge pull request #9422 from tonk/docfix

Ignore compiled Python for documentation.
Merge pull request #9425 from bobobox/patch-1

Typo fix in playbooks_intro.rst
Merge pull request #9216 from nmadhok/patch-3

Update playbooks_roles.rst
More v2 roles class work

* added ability to set parents (will be used when the deps are loaded)
* added role caching, so roles are not reloaded needlessly (and for
  use in detecting when roles have already been run)
* reworked the way metadata was stored - now individual attribute fields
  instead of a dictionary blob
Adding role deps to v2 Role class and fixing some bugs
added fact caching hint
Add a changelog entry for how the git module has changed.
Pull in git submodule tracking
Add branch info for our submodules
Test the git changes for the git module's recursive flag
Remove test case that wasn't reported as something git should do