Describe the feature or problem you’d like to solve

I've been reviewing many PRs recently, and the workflow is typically:

gh pr checkout <PR number>
gh pr merge <PR number>
git switch main
git branch -D <PR name>
git pull

I tried using gh pr merge -d

gh pr checkout <PR number>
gh pr merge -d <PR number>

as it automatically

1. deletes local and remote branches
2. switches to default branch
3. pulls the merged commit

but it does not work due to reasons mentioned in #2860.

Proposed solution

almost every time when i review a PR from other's fork,

1. i want to keep their remote branch (as it's theirs)
2. but i want to delete the local PR branch i've gh pr checkouted (to keep my local branches clean), then switch to main and pull the changes.

a new flag, --delete-local could address this issue. after the feature gets added, my workflow would look like:

gh pr checkout <PR number>
gh pr merge --delete-local <PR number>