Changed Library to Libraries for grammer.
Changed 'Convenience' to 'Convenient' for grammer.
Removed 'an' from sentence. Also never start a sentence with 'And' while I'm in there :)
Update controllers.rst
Merge pull request #775 from deoradharmendra/patch-1

Update controllers.rst
Merge pull request #772 from KareemSaleh/fix-grammer

Changed Some words for small grammar fix.
[fr] Follow #772

Changed Some words for small grammar fix.
[fr] Follow #775

Update controllers.rst