Documentation update.
* mr/doc-clean-f-f:
Documentation/git-clean.txt: document that -f may need to be given twice
-f::
--force::
If the Git configuration variable clean.requireForce is not set
- to false, 'git clean' will refuse to run unless given -f, -n or
- -i.
+ to false, 'git clean' will refuse to delete files or directories
+ unless given -f, -n or -i. Git will refuse to delete directories
+ with .git sub directory or file unless a second -f
+ is given. This affects also git submodules where the storage area
+ of the removed submodule under .git/modules/ is not removed until
+ -f is given twice.
-i::
--interactive::