Improve scroll behavior when folding files on pull request "files changed" tab

[HesterG]

Close #23515

As described in the issue above, right now when "fold file" icon or "viewed" is clicked to fold files, it will scroll to the position before folding, resulting in confusing file jumping when scrollY is greater than certain value(approximately the offsetTop of current diff file header). This PR is to adjust scrolling behavior when folding the files (no scrolling when expanding the files).

Files can be folded in two ways: clicking viewed or clicking "fold file" icon. The folding of these two behaviors will be a little different in this PR(which can be discussed):

1. If folded by clicking "fold file" icon and the scrollY is greater than current diff file header, scroll to header of the folded file.
2. If folded by clicking "viewed" checkbox and the scrollY is greater than current diff file header, scroll to next file.

File folding behavior after this PR:

default.mov

Update:

Make the behavior the same in both cases(first behavior)

default.mov

[codecov-commenter]

Codecov Report

Merging #23604 (bc5c8ea) into main (f521e88) will increase coverage by 0.02%.
The diff coverage is 29.90%.

❗ Current head bc5c8ea differs from pull request most recent head 07c6ec5. Consider uploading reports for the commit 07c6ec5 to get more accurate results

@@            Coverage Diff             @@
##             main   #23604      +/-   ##
==========================================
+ Coverage   47.14%   47.17%   +0.02%     
==========================================
  Files        1149     1154       +5     
  Lines      151446   152327     +881     
==========================================
+ Hits        71397    71854     +457     
- Misses      71611    71992     +381     
- Partials     8438     8481      +43     

Impacted Files	Coverage Δ
cmd/dump.go	0.67% <0.00%> (ø)
cmd/web.go	0.00% <0.00%> (ø)
models/actions/run.go	1.64% <0.00%> (-0.08%)	⬇️
models/actions/runner.go	1.44% <ø> (ø)
models/packages/package.go	45.45% <0.00%> (-1.13%)	⬇️
models/user/search.go	77.50% <0.00%> (-6.29%)	⬇️
modules/actions/github.go	0.00% <0.00%> (ø)
modules/actions/workflows.go	0.00% <0.00%> (ø)
modules/context/context.go	64.54% <0.00%> (-3.53%)	⬇️
modules/doctor/storage.go	31.93% <0.00%> (ø)
... and 28 more

... and 38 files with indirect coverage changes

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[gempir]

I think behaviour 1. is great.

But 2. looks a little odd to me. I think when a user clicks on an UI element and then suddenly that UI element is gone from his view he might be confused. Ideally the filled checkbox of "viewed" would still be directly under the cursor of the user.
This costs a little more space, but gives the user feedback on his change in a way.

At least that sounds more intuitive behaviour to me, no?

[HesterG]

I think behaviour 1. is great.

But 2. looks a little odd to me. I think when a user clicks on an UI element and then suddenly that UI element is gone from his view he might be confused. Ideally the filled checkbox of "viewed" would still be directly under the cursor of the user. This costs a little more space, but gives the user feedback on his change in a way.

At least that sounds more intuitive behaviour to me, no?

Yes I think so. And I think that means to make them have the same behavior (1st one). Added a commit to change that, please check the update video in description or checkout to try.

[gempir]

Don't have the time to check it out locally right now but from the video it looks great!
I think this makes a ton of sense UI wise and is easy for the user to understand.

Thank you! ❤️

[wxiaoguang]

There is an alternate ?

• Scroll collapsed file into view #23702