Describe the bug

> gh pr merge 184 --delete-branch
? What merge method would you like to use? Create a merge commit
? Delete the branch locally and on GitHub? (y/N)

I would expect it to not ask me about deleting. Same behavior with -d.

Steps to reproduce the behavior

1. Make a branch
2. Merge it via gh pr merge «pr number» --delete-branch
3. See that you are still asked about deleting the branch

Expected vs actual behavior

Expecting it to not ask and delete the branch.

Version

macOs catalina, via homebrew:

> gh --version
gh version 1.4.0 (2020-12-15)
https://github.com/cli/cli/releases/latest