Update core modules for docker fix
Improve wording in playbooks_intro.rst

I was reading the docs and thought "that wording seems off."
Fix some typos in developing_modules.rst
Merge pull request #9908 from NateEag/patch-2

Improve wording in playbooks_intro.rst
Merge pull request #9910 from NateEag/patch-3

Fix some typos in developing_modules.rst