The b4 contributor guide sits in the coding-style document, which is an odd place for it. Move it into sending_patches.rst, next to the patman note, so both patch-sending tools are described together. The b4_contrib label moves with it, so the reference from process.rst still resolves. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org> Reviewed-by: Tom Rini <trini@konsulko.com>