Steps to replicate the issue (include links if applicable):

• Open the template data editor for a template
• Click "Add parameter" at the bottom

What happens?:

Nothing is focused.

What should have happened instead?:

The input field should be focused, so that the user can start entering the parameter name.

Software version (skip for WMF-hosted wikis like Wikipedia):

Other information (browser name/version, screenshots, etc.):