Documentation: git-clean: fix minor grammatical errors
Documentation: git-clean: fix minor grammatical errors

There were a few minor grammatical errors that made this paragraph hard
to read. This patch fixes the errors in a very minimal manner.

Signed-off-by: Wesley J. Landaker <b4bb62cb2c6558af9e884d5ae3d3f535b22bb4cf@icecavern.net>
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