I'm not sure if this is a bug per se but a small bother.

In [deleting unwanted files](https://git-annex.branchable.com/tips/deleting_unwanted_files/) it is mentioned that you can use `git annex drop --force $file` to make it go away. But after that when fsck is run it will warn that there are no copies and that it should be marked as dead. And if it's deleted from the branch it will still complain if fsck is run with `--all`.

Shouldn't they be marked dead automatically if the copy count reaches 0?

Example:

[[!format sh """
$ git annex fsck 
fsck test 
  ** No known copies exist of test
failed
(recording state in git...)
git-annex: fsck: 1 failed
$ rm test
$ git annex fsck --all
$ fsck SHA256E-s16--c21f3ac6b5f6e45b1c0b292bcd5cc806298ecb033bc7030a6071e3c894d73054 
  ** No known copies exist of SHA256E-s16--c21f3ac6b5f6e45b1c0b292bcd5cc806298ecb033bc7030a6071e3c894d73054

  (Avoid this check by running: git annex dead --key )
failed
(recording state in git...)
git-annex: fsck: 1 failed
$ git annex forget --force
$ git annex repair --force
$ git annex fsck --all
fsck SHA256E-s16--c21f3ac6b5f6e45b1c0b292bcd5cc806298ecb033bc7030a6071e3c894d73054 
  ** No known copies exist of SHA256E-s16--c21f3ac6b5f6e45b1c0b292bcd5cc806298ecb033bc7030a6071e3c894d73054

  (Avoid this check by running: git annex dead --key )
failed
(recording state in git...)
git-annex: fsck: 1 failed
"""]]

From this, not even forget,fsck or repair can make this go away but only `git annex dead --key` which can be a pain to call it on a ton of different keys (there doesn't appear to be an option to batch mark them all as dead either).




Additionally the key will still remain in the `git-annex` branch, I'm not sure about the internal optimizations in place but I'd assume leaving unused keys around in the branch can cause slowdowns when it's checked out/updated in repositories with a lot of add/update/delete activity.


### Have you had any luck using git-annex before? (Sometimes we get tired of reading bug reports all day and a lil' positive end note does wonders)

I'm using git annex to manage all my personal data, thanks for making such an amazing piece of software :)
