Add headerbar in the simultaneous translation menu

[HotarunIchijou]

Describe your suggested feature

I was thinking for a long time what's wrong with simultaneous translation menu and I finally understood: there's no headerbar. So please add it.

Other details

No response

Acknowledgements

• [X] I have searched the existing issues and this is a new ticket, NOT a duplicate or related to another open issue.
• [X] I have written a short but informative title.
• [X] I will fill out all of the requested information in this form.

[Bnyro]

You mean the dialog?

[HotarunIchijou]

Yes