Add clarifying output suggesting how dev can solve gettext error when
running lefthook run pre-push

- The rubocop server is incompatible with usage of ENV vars to dynamically
  control content of the .rubocop.yml config, because changes to ENV
  vars are not picked up or respected, the server caches the current
  state of ENV vars when it starts.

Adds a `pre-push` hook to check name clashing between `db` migrations and `Elasticsearch` migrations.

Some developers tend to disable pre-commit hooks to speed up their flow
so having RuboCop run in pre-push (as a safety net) is crucial.

Running rubocop checks on push is frustrating, as correcting any errors
requires either a new commit or an --amend. By moving rubocop checks to
pre_commit, we can instead prevent issues it complains about from
entering the tree entirely, helping users to prevent stubbing their toe
when they later attempt to push.

Create a rake task to auto generate documentation for all the available
audit event types.

Excluding doc/api/graphql/reference/index.md
from vale, markdown-lint and docs-trailing_spaces

With this, we no longer need to run `rubocop` with `--config
.rubocop.yml` in monorepo or gem directory.

Now, running `rubocop` in both monorepo and gems/ directories behaves as
expected:
1. In monorepo, inspecting files with `--force-exclusion` from gems/ is a
   no-op
2. In gems/, inspect files works without passing `--config .rubocop.yml`

This is a workaround to RuboCop's behavior/bug:
See https://gitlab.com/gitlab-org/gitlab/-/merge_requests/125735#note_1462062385

The performance of generating translations was greatly increased, which
means we can run it before pushing. This should save some unnecessary
broken pipelines.

The deprecation and removals pages are being combined
so we need to remove the removal-specific tasks

A custom lefthook target to run all the linters with with auto-fix
capabilities, but just on the files which changed in your branch.

```shell
# If installed globally
lefthook run auto-fix
# Or if installed via ruby gem
bundle exec lefthook run auto-fix
```

Terminates the pipeline schema validation if changes are introduced
to the structure file without using migrations. This behavior could
be overridden by using pipeline:change-schema-without-migrations
label when necessary.

Changelog: changed

This will match files like config/gitlab.yml.example.

To make it easier for contributors to rebase their forks.

Having `REVEAL_RUBOCOP_TODO=1` reveals RuboCop TODOs also for HAML lint
which and sometimes prevents pushing code.

This commit hides any RuboCop TODOs in lefthook also for HAML lint.

This will reduce the boilerplate code.

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