add fuzzy finder in branch list

[UUGTech]

This PR is related to #1350.

Hi @extrawurst,

Sorry for my poor English. But I have a small PR!
I implemented a fuzzy finder pop-up in the branch list.
This may make it easier to find the branch you want to select.

Instead of a pop-up, we could implement as an embedded finder in the branch list, but I don't think this is a good idea as it would change the look and feel a lot.
So I have implemented it as a pop-up.
The implementation is almost the same as file_find_popup.

It changes the following:

• add branch finder popup to branchlist component

Here is how it works in the implementation in this PR.

I followed the checklist:

• I added unittests
• I ran make check without errors
• I tested the overall application
• I added an appropriate item to the changelog

[extrawurst]

Thanks for tackling this. This PR is already in very good shape. My comments are mostly nitpicky (aside the common base maybe). let me know if you feel up for the extraction part. if not I would like this to be merged without it to make it part of the next release

[UUGTech]

Thank you for your review.
I replied to your comments.
If I make common base for fuzzy_find, the picky issues of FileFindPopup I commented in reply also will be solved.
I'll work on that.

[extrawurst]

let me know when its ready for the final review

[UUGTech]

Ok, when it's ready for the final review, I re-request review.

Before that, I have a small question.
Which is better command info?

Scroll[...] Close[⎋] Close[⏎]
Scroll[...] Close[⎋⏎]

[UUGTech]

It is now ready for review.
Command info is now Scroll[...] Close[⎋⏎].
If you think this is not good, I will fix it.
Otherwise, you can merge this.

[extrawurst]

Thanks a lot!

[extrawurst]

added changelog entry for you including gif showcase:

[UUGTech]

I had completely forgotten about the changelog. 🙇‍♂️
Thank you so much!