## Description
When a win is relative = "win" it should size itself relative to that
win's size. Currently this only happens correctly when the picker layout
is created. All subsequent updates, such as a toggle_preview action, can
potentially trigger calls to a function width/height opt with a
max_width and max_height smaller than was previously calculated. This
feeds into a recursive series of updates triggered by the WinResized
event triggering and updating with a yet smaller max_width or
max_height.
Additionally, because win.o.cols and win.o.lines is used,
relative/decimal dimensions would not calculate correctly in splits.
Screenshots are from a picker configured as
```
{
col = 1,
height = 0.9,
width = 0.9,
position = 'float',
relative = 'win',
}
```
**before**
<img width="1348" height="1358" alt="image"
src="https://github.com/user-attachments/assets/847b0565-afd0-4ca1-b44c-eb63e335afca"
/>
**after**
<img width="1354" height="1354" alt="image"
src="https://github.com/user-attachments/assets/064f25ae-ed17-42c8-8b34-f32652fab02d"
/>
## Description
More info coming tomorrow.
In short:
- very fast. pretty much realtime filtering/sorting in huge repos (like
1.7 million files)
- extensible
- easy to customize the layout (and lots of presets) with
`snacks.layout`
- simple to create custom pickers
- `vim.ui.select`
- lots of builtin pickers
- uses treesitter highlighting wherever it makes sense
- fast lua fuzzy matcher which supports the [fzf
syntax](https://junegunn.github.io/fzf/search-syntax/) and additionally
supports field filters, like `file:lua$ 'function`
There's no snacks picker command, just use lua.
```lua
-- all pickers
Snacks.picker()
-- run files picker
Snacks.picker.files(opts)
Snacks.picker.pick("files", opts)
Snacks.picker.pick({source = "files", ...})
```
<!-- Describe the big picture of your changes to communicate to the
maintainers
why we should accept this pull request. -->
## Todo
- [x] issue with preview loc not always correct when scrolling fast in
list (probably due to `snacks.scroll`)
- [x] `grep` (`live_grep`) is sometimes too fast in large repos and can
impact ui rendering. Not very noticeable, but something I want to look
at.
- [x] docs
- [x] treesitter highlights are broken. Messed something up somewhere
## Related Issue(s)
<!--
If this PR fixes any issues, please link to the issue here.
- Fixes #<issue_number>
-->
## Screenshots
<!-- Add screenshots of the changes if applicable. -->
