git submodule add: Remove old docs about implicit -f
git submodule add: Remove old docs about implicit -f

git submodule add no longer implicitly adds with --force. Remove
references to the old functionality in the documentation.

Signed-off-by: Ævar Arnfjörð Bjarmason <0135fcc047f75af264c800977a73e353c6ba842d@gmail.com>
Acked-by: Jens Lehmann <3a81d01482cca860e4077eb409d7db78ebdc6f24@web.de>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git