[TYPO3-doc] Encouraging people to contribute with Github

[Fabien Udriot]

>> * Start editing and when finish, press at the bottom the "Propose file
>> change" (well, don't do that
> 
> Is there a way to sync forks without command line?
> 
> Because that is IMHO the biggest drawback.

Actually this is not strictly needed for us. Every time you enter this kind of URL and validate a
change, the system will create a *new branch* in your forked repository which is in sync with the
master.

https://github.com/zendframework/zf2-documentation/edit/master/docs/languages/en/user-guide/overview.rst

Besides that, and more generally speaking, I don't think Github can make a sync of a repository from
the web interface and CLI commands will be required https://help.github.com/articles/syncing-a-fork.
For casual contributors, it could be easier to drop the repository and re-fork. I know it sounds a
bit brute force!

Fb.