Make a note about CamelCased Theme Names

Adds a call out regarding CamelCased theme names in the docs.
Grammar correction from its to it is
Merge pull request #1373 from jtyost2/patch-1

Make a note about CamelCased Theme Names
Update helpers.rst
Update text.rst
Merge pull request #1374 from alanfgh/patch-22

Update helpers.rst
Merge pull request #1375 from alanfgh/patch-23

Update text.rst