en/present-despite-skipped (Re: What's cooking in git.git (Feb 2022, #05; Thu, 17))

> * en/present-despite-skipped (2022-01-14) 6 commits
>   (merged to 'next' on 2022-02-15 at 960873fdad)
>  + Accelerate clear_skip_worktree_from_present_files() by caching
>  + Update documentation related to sparsity and the skip-worktree bit
>  + repo_read_index: clear SKIP_WORKTREE bit from files present in worktree
>  + unpack-trees: fix accidental loss of user changes
>  + t1011: add testcase demonstrating accidental loss of user modifications
>  + Merge branch 'vd/sparse-clean-etc' into en/present-despite-skipped
>
>  In sparse-checkouts, files mis-marked as missing from the working tree
>  could lead to later problems.  Such files were hard to discover, and
>  harder to correct.  Automatically detecting and correcting the marking
>  of such files has been added to avoid these problems.
>
>  Will merge to 'master'.
>  cf. <20220204081336.3194538-1-newren@gmail.com>
>  source: <pull.1114.v2.git.1642175983.gitgitgadget@gmail.com>