Demote "Working with Git" within committing.rst (#285)
Demote "Working with Git" within committing.rst (#285)

Makes committing.rst consistent with the rest of the guide in having
just one top-level section. This eliminates a surprise navigation where
18 comes next after 16.
jython/devguide,jeff5/jython-devguide,jython/devguide,jython/devguide,jeff5/jython-devguide,jeff5/jython-devguide,ezio-melotti/devguide