git-cl documentation and issue #4666

[Paul Morris]

Hi James,

I thought your CG edits in issue 4666 were a really helpful improvement:
https://sourceforge.net/p/testlilyissues/issues/4666/

Did you intend to keep this git-cl info (install and configuration) in the 
3.3.4 Commits and Patches section, so that it is repeated in both places?  
Seems like 3.3.4 should now just link to 2.3 git-cl for install, update, and 
configuration instructions.  

(Currently one has to scroll past the install and configure section each time 
one consults the docs about how to create or upload a patch for review.)

-Paul