changes: @user a Zoom call was added to this issue
into: @user added a Zoom call to this issue

Same concept appleis for "removed"

Add a zoom link added / removed system note when a zoom link is being
added / removed to the issue description.

These are not required because MySQL is not
supported anymore

Although `flat_map` is equivalent to `map` + `flatten(1)`
(note the level 1) we can apply this same refactoring to all cases.

Task list updates should not mark users action as spam on akismet.

to support manual sorting on the frontend

Probably useful as we often move these files to "new" files.

Add project when creating milestone in specs

We validate milestone is from the same
project/parent group as issuable ->
we need to set project in specs correctly

Improve methods names and specs organization

Allow single tasks to be updated quickly

Fix leaking information of confidential issues on TODOs
when user is downgraded to guest access.

Signed-off-by: NRémy Coutable <remy@rymai.me>

This ensures the open issues/MR count caches are refreshed properly when
creating new issues or MRs. This MR also includes a change to the cache
keys to ensure all caches are rebuilt on the fly.

This particular problem was not caught in the test suite due to a null
cache being used, resulting in all calls that would use a cache using
the underlying data directly. In production the code would fail because
a newly saved record returns an empty hash in #changes meaning checks
such as `state_changed? || confidential_changed?` would return false for
new rows, thus never updating the counters.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/38061

We were incorrectly stubbing `Issues::MoveService#execute`. This only
caused a failure when another spec caused it to be autoloaded --
`spec/controllers/projects/issues_controller_spec.rb` in this case.

 Update to add all issues to be updated.
 Added functionality, proper tests, documentation and changelog.

Signed-off-by: NRémy Coutable <remy@rymai.me>

`:mailer` is needed to pick it easily, while
`type: :mailer` is needed for picking it automatically for
tests located in spec/mailers/*_spec.rb

It's a bit complicated in spec/services/notification_service_spec.rb
but we'll leave it alone for now.