Hello! The documentation for git-rm at
Removes all *.txt files from the index that are under the
Documentation directory and any of its subdirectories. The files are not
removed from the working tree.
I think that this should say
git-rm --cached Documentation/\*.txt
Otherwise I don't see why it wouldn't remove the files from the working
tree. If this is a documentation error, it could cause some bad
problems for people who follow it.