Remove/reword Git "regular expression" support

[benjamin051000]

https://github.com/adambard/learnxinyminutes-docs/blob/8498d0254a139e037eecac2acc389785a74a56c7/git.html.markdown?plain=1#L195-L196

This is not regular expressions, it's actually pathname expansion (AKA glob patterns) , which is done by the shell. Therefore, these lines should be removed or reworded for clarity. While useful when running git commands, they technically have nothing to do with git itself.

If you feel strongly about keeping this section, I'd recommend the following wording:

# Shell glob patterns make it easy to specify multiple files:
$ git add ./*.java