Allow file pattern filters when using a commit filter

[Drise13]

Looking for something that satisfies the following command:

'dotnet regitlint -f commits -a head^ -b head -p "**/*.cs"

[bart-vmware]

This command could mean two things:

• Reformat only the *.cs files from the last commit
• Reformat all files changed in the last commit, and also run on all files that match *.cs

Besides that, this is very tricky to get right, because today the pattern is simply passed onto cleanupcode. And cleanupcode is full of bugs in handling glob patterns (which may change at any time). So now regitlint would need to re-implement that buggy behavior, so it can apply the equivalent filtering logic on the found files from git.

Another approach could be to use .NETs own file globbing on the found git files. But that would mean regitlint gets two different interpretations for globs, depending on whether you combine it with commit hashes or not.

Neither sound very appealing. A third option (breaking change) could be to never send the pattern onto cleanupcode, but make regitlint always expand the pattern into a fileset. That raises the question how to deal with conflicting include/exclude patterns (who wins?). It also makes running regitlint on a large set of files magnitudes slower, because now it needs to break the set into individual calls to cleanupcode because of command-line length restrictions.