Merge branch 'jk/diff-honor-wserrhighlight-in-plumbing'

The diff-* plumbing family of subcommands now pay attention to the diff.wsErrorHighlight configuration, which has been ignored before; this allows "git add -p" to also show the whitespace problems to the end user. * jk/diff-honor-wserrhighlight-in-plumbing: diff: move diff.wsErrorHighlight to "basic" config