CLI version: 1.0.0 🚀
Related: #695

Describe the bug

• gh <tab> does not offer completions, even after running gh completion --shell powershell |Out-String |Invoke-Expression.
• However, gh <command> <tab> does offer completions.

Steps to reproduce the behavior

1. Open Powershell
2. Type gh
3. Press tab.
4. No completion occurs.

Expected vs actual behavior

Expected gh + tab to complete.