Update message shown when unsharing a file

[kevgathuku]

Attempts to fix #9180

[MorrisJobke]

Makes sense to me 👍

[MorrisJobke]

The CI failure is, because the commit message is missing the sign-off message. You can read more about this at https://github.com/nextcloud/server/blob/master/CONTRIBUTING.md#sign-your-work

If you have this branch checked out locally, you could adjust the existing commit by doing this:

git commit --amend -s
git push -f origin update-unshare-message

And welcome as first-time contributor to the Nextcloud project. 🎉

[codecov]

Codecov Report

Merging #9893 into master will not change coverage.
The diff coverage is 0%.

@@            Coverage Diff            @@
##             master    #9893   +/-   ##
=========================================
  Coverage     51.92%   51.92%           
  Complexity    25804    25804           
=========================================
  Files          1637     1637           
  Lines         95501    95501           
  Branches       1318     1318           
=========================================
  Hits          49592    49592           
  Misses        45909    45909

Impacted Files	Coverage Δ	Complexity Δ
...pps/files_sharing/lib/Activity/Providers/Users.php	0% <0%> (ø)	23 <0> (ø)	⬇️
apps/files_trashbin/lib/Trashbin.php	72.46% <0%> (-0.25%)	136% <0%> (ø)
lib/private/Files/Cache/Propagator.php	96.2% <0%> (+1.26%)	16% <0%> (ø)	⬇️

[kevgathuku]

Thanks for the pointers @MorrisJobke. I've been able to add the sign-off message.
And thanks for the welcome, it's exciting to contribute to this awesome project 😄