fix problem with slash in branch name on Windows

[nebulon42]

In 3d1b6f1 OS specific handling was added for line endings and path separators when executing Git commands.

This was over-generalizing the problem because the response of a Git command can also include a branch name and if that branch name would contain a slash (e.g. feature/my-feature) then this would be changed to a backslash on Windows which does not work.

I have removed the path separator handling from the Git command output and moved it instead to the changed file processing location.

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