Merge branch 'rs/diff-exit-code-fix' into maint-2.46

In a few corner cases "git diff --exit-code" failed to report "changes" (e.g., renamed without any content change), which has been corrected. * rs/diff-exit-code-fix: diff: report dirty submodules as changes in builtin_diff() diff: report copies and renames as changes in run_diff_cmd()