fix: correct patch commands for recursive diffs

[kormide]

To correctly apply a recursive patch in the source tree from one folder dir_a to another dir_b, we need to change directories and subtract the right prefix.

Produces a message like:

ERROR: diff command exited with non-zero status.

To accept the diff, run:
(cd $(bazel info workspace); patch --directory diff/tests/case_recursive.dir_a -p3 < bazel-out/k8-fastbuild/bin/diff/tests/case_recursive.patch)