Merge branch 'sb/submodule-recursive-absorb'

When a submodule "A", which has another submodule "B" nested within it, is "absorbed" into the top-level superproject, the inner submodule "B" used to be left in a strange state. The logic to adjust the .git pointers in these submodules has been corrected. * sb/submodule-recursive-absorb: submodule absorbing: fix worktree/gitdir pointers recursively for non-moves cache.h: expose the dying procedure for reading gitlinks setup: add gentle version of resolve_git_dir