git: Use `zebra` for moved line colors
git: Use `zebra` for moved line colors

This change uses a git 2.15 feature to change the diff colors for lines
that have been moved rather than added or deleted. It provides a cue to
readers that a line's content has not changed.

Adding this setting in gitconfig should not break earlier git. (Tested
against 2.14 and the change had no effect.)

toobulkeh/dotfiles,moofish32/dotfiles,ren/dotfiles,bschmoker/dotfiles,bschmoker/dotfiles,tchiarato/dotfiles,koerbcm/dotfiles,koerbcm/dotfiles,YepengFan/dotfiles,koerbcm/dotfiles,astoellis/dotfiles,koerbcm/dotfiles,moofish32/dotfiles,astoellis/dotfiles,koerbcm/dotfiles,YepengFan/dotfiles,tchiarato/dotfiles,ren/dotfiles