Merge branch 'fix/rename-mwbs-to-merge-when-pipeline-succeeds' into 'master'
Rename MWBS service to Merge When Pipeline Succeeds
## What does this MR do?
This MR renames Merge When Build Succeeds feature to Merge When Pipeline Succeeds, because we recently changed the behavior, see https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6675.
## Does this MR meet the acceptance criteria?
- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] All builds are passing
## What are the relevant issue numbers?
Closes #23354
See merge request !7135