[[PR Description]]

- Adds some Story components to reduce the amount of code needed to lay
out stories
- Added the ability to open a story in Zed using a link (see text story)
- Added sections with descriptions and usage.

Release Notes:

- N/A

It seems to have been lost in the recent styling pass.

Release Notes:

- N/A

Release Notes:

- N/A

In zed1, cmd-f either opened the search buffer, or focused into it if it
was open already. Search query got updated, if any selection was made on
the moment of cmd-f call.

The PR restores that behavior and also

* fixes a bug when opened diagnostics error always got pasted
* comments out the panic on multibuffer separator click 
* removes extra stdout & stderr debug logging

Release Notes:

- N/A

See title

Any focus changes which fire from within a focus handler should be
handled in the next frame

Release Notes:

- N/A

Release Notes:

- N/A

As it says on the tin

Release Notes:

-

In the 3 charts below, "window draw" has 3 major subroutines. Request
layout, where we walk over the tree and have everything talk to the
layout engine initially. Compute layout, where we have the layout engine
actually do the layout, and then paint, where we use the computed bounds
to populate the scene.


![image_720](https://github.com/zed-industries/zed/assets/1789/d2225389-865f-4c8a-9452-9f611da64dcf)

Things are moving quickly so before/after comparisons are tough. In the
graph above, green bars are from a commit actually pre-dates a merge of
master which increased the complexity of layout. The red bars represent
the state of the world after this PR. Note how we improve the
performance of `paint`.

Improvements:

- Not moving `self` in `Element::paint`. This was moving from the heap
to the stack and imposing a big cost. This is the biggest win in this
PR.
- We got some minor wins by making the stacking order a bigger smallvec
of u8 instead of u32.
- A big win that doesn't show up in this chart is avoiding a double
render of the editor when autoscrolling by never pushing notification
effects or marking the window dirty when notifying during a window draw.

Release Notes:

- N/A

The formatting of the empty pane text regressed in #3665, in which I
also made it possible to drag items onto an empty pane.

Reimplement the pane drag targets using on_drag_move

Reimplement the pane drag targets using on_drag_move

This fixes some bugs in the display and tracking of dock resizes

Release Notes:

-

co-authored-by: conrad <conrad@zed.dev>

This PR fixes a warning that was present in release mode, which was
preventing the nightly builds from running:

```
error: variable does not need to be mutable
   --> crates/gpui2/src/elements/div.rs:547:9
    |
547 |     let mut div = Div {
    |         ----^^^
    |         |
    |         help: remove this `mut`
    |
    = note: `-D unused-mut` implied by `-D warnings`
```

Release Notes:

- N/A

co-authored-by: conrad <conrad@zed.dev>

This PR populates the `editor_foreground` color in the various themes
and updates the editor to use this as the color for text.

The `text` field in the theme should now be used for UI elements, while
`editor_foreground` should be used for buffers.

This improves the contrast in some themes, notably Ayu Dark.

Release Notes:

- N/A