Refined-github: Avoid jump caused by recently pushed branches

[fregante]

This is generally useful, but sometimes you can't send a PR _right now_ so it'll keep pushing your content down about a second after page load, messing with your clicks. Perhaps we can make this less intrusive?

[fregante]

Example:

1. groupButtons() out of New pull request
2. Add button with dropdown icon
3. Move .RecentBranches to a <detail><summary> like GH does everywhere
4. Hide Compare && pull request text from buttons

This would make it hidden inside the dropdown, which will only appear when fresh branches are available.

However it would be hard to pull off since we'd have to watch for the fresh branches to show/hide the dropdown.

[hkdobrev]

I like the visibility of it and I always use it when I haven't created the PR through hub already. I see team members use it as well.

I'm 👍 on changing it to not push content, but I don't want to hide it under a button click. It could be like a dismissable alert or a drop down opening by default.

[fregante]

I like the visibility of it

Agreed, perhaps it's best to just make it a position: absolute overlay so it doesn't push things down.

Making it dismissable however is a whole other can of worms.

[hkdobrev]

99% of the cases you would have it for a single branch, we could probably shrink it just a bit so it fits the height of the tab row and looks nicer.