Merge branch 'en/t6036-merge-recursive-tests'

Tests to cover various conflicting cases have been added for merge-recursive. * en/t6036-merge-recursive-tests: t6036: add a failed conflict detection case: regular files, different modes t6036: add a failed conflict detection case with conflicting types t6036: add a failed conflict detection case with submodule add/add t6036: add a failed conflict detection case with submodule modify/modify t6036: add a failed conflict detection case with symlink add/add t6036: add a failed conflict detection case with symlink modify/modify