ci: rebase before release push in manual_version_docs

Adds `pull: '--rebase --autostash'` to the EndBug/add-and-commit step
that pushes versioned docs, avoiding push failures when the branch has
moved ahead.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: B4nan

.github/workflows/manual_version_docs.yaml

@@ -130,6 +130,7 @@ jobs:
           add: website/versioned_docs website/versioned_sidebars website/versions.json
           message: "docs: Version docs for v${{ steps.snapshot.outputs.version }} [skip ci]"
           default_author: github_actions
+          pull: '--rebase --autostash'
 
       - name: Resolve output commitish
         id: resolve_commitish