Releasey: Automatically create PRs for documentation updates

### Is your feature request related to a problem? Please describe.

The manual steps described by #3476 can be automated and added to either the 3rd or 4th releasey workflow, to let the workflow create the PRs against the `versioned-docs` and `main` branches.

### Describe the solution you'd like

_No response_

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

Start by reading issue #3476 and locating the 3rd and 4th Releasey workflows in the repository. Trace the existing manual documentation-update steps and determine how PRs should be created against the versioned-docs and main branches; done means the selected workflow creates both PRs reliably.

Written by the indexing model from the issue text.