Release Notes:

- N/A

This PR takes a different approach to input handling.

Rather than returning the optional input handler, focus handle pair from
the element trait, we instead allow you to register an input handler
imperatively on the window context with `WindowContext::handle_input`.
You pass a focus handle reference and any implementer of
`PlatformInputHandler`. There's an `ElementInputHandler<V>` that
implements `PlatformWindowHandler` so long as `V` implements
`InputHandler`.

Release Notes:

- N/A

port rope2 to zed2

Release Notes:

- NA

This removes a lot of ad-hoc event translation code in the workspace and
replaces it with a GPUI feature and trait bounds.

TODO:
- [x] Proof out idea
- [x] Convert the workspace
- [x] Convert the rest of the app

Release Notes:

- N/A

Remove some debugging from GoToLine

Release Notes:

- N/A

![Screenshot 2023-11-08 at 5 33
10 PM](https://github.com/zed-industries/zed/assets/326587/09efd785-2c43-41b2-9429-c17067497fd2)

![Screenshot 2023-11-08 at 5 33
28 PM](https://github.com/zed-industries/zed/assets/326587/14a9faee-3547-40b6-a31f-16f653cdcb36)

- MODAL
- center a div
- MOAR CODE
- Beautiful go to line modal


Release Notes:
- N/A

Co-authored-by: Marshall <marshall@zed.dev>

Provide element bounds to the input handler's `bounds_for_rect` method.

Co-authored-by: Marshall <marshall@zed.dev>

Co-authored-by: Marshall <marshall@zed.dev>

This also introduces new APIs in `ViewContext` for observing window
focus changes.

Release Notes:

- N/A

[[PR Description]]

Adds documentation to ColorScaleSteps:

```rust
/// Returns the specified step in the [`ColorScale`].
    #[inline]
    pub fn step(&self, step: ColorScaleStep) -> Hsla {
        // Steps are one-based, so we need convert to the zero-based vec index.
        self.0[step.0 - 1]
    }

    /// `Step 1` - Used for main application backgrounds.
    ///
    /// This step provides a neutral base for any overlaying components, ideal for applications' main backdrop or empty spaces such as canvas areas.
    ///
    #[inline]
    pub fn step_1(&self) -> Hsla {
        self.step(ColorScaleStep::ONE)
    }

    /// `Step 2` - Used for both main application backgrounds and subtle component backgrounds.
    ///
    /// Like `Step 1`, this step allows variations in background styles, from striped tables, sidebar backgrounds, to card backgrounds.
    #[inline]
    pub fn step_2(&self) -> Hsla {
        self.step(ColorScaleStep::TWO)
    }

    /// `Step 3` - Used for UI component backgrounds in their normal states.
    ///
    /// This step maintains accessibility by guaranteeing a contrast ratio of 4.5:1 with steps 11 and 12 for text. It could also suit hover states for transparent components.
    #[inline]
    pub fn step_3(&self) -> Hsla {
        self.step(ColorScaleStep::THREE)
    }

    /// `Step 4` - Used for UI component backgrounds in their hover states.
    ///
    /// Also suited for pressed or selected states of components with a transparent background.
    #[inline]
    pub fn step_4(&self) -> Hsla {
        self.step(ColorScaleStep::FOUR)
    }

    /// `Step 5` - Used for UI component backgrounds in their pressed or selected states.
    #[inline]
    pub fn step_5(&self) -> Hsla {
        self.step(ColorScaleStep::FIVE)
    }

    /// `Step 6` - Used for subtle borders on non-interactive components.
    ///
    /// Its usage spans from sidebars' borders, headers' dividers, cards' outlines, to alerts' edges and separators.
    #[inline]
    pub fn step_6(&self) -> Hsla {
        self.step(ColorScaleStep::SIX)
    }

    /// `Step 7` - Used for subtle borders on interactive components.
    ///
    /// This step subtly delineates the boundary of elements users interact with.
    #[inline]
    pub fn step_7(&self) -> Hsla {
        self.step(ColorScaleStep::SEVEN)
    }

    /// `Step 8` - Used for stronger borders on interactive components and focus rings.
    ///
    /// It strengthens the visibility and accessibility of active elements and their focus states.
    #[inline]
    pub fn step_8(&self) -> Hsla {
        self.step(ColorScaleStep::EIGHT)
    }

    /// `Step 9` - Used for solid backgrounds.
    ///
    /// `Step 9` is the most saturated step, having the least mix of white or black.
    ///
    /// Due to its high chroma, `Step 9` is versatile and particularly useful for semantic colors such as
    /// error, warning, and success indicators.
    #[inline]
    pub fn step_9(&self) -> Hsla {
        self.step(ColorScaleStep::NINE)
    }

    /// `Step 10` - Used for hovered or active solid backgrounds, particularly when `Step 9` is their normal state.
    #[inline]
    pub fn step_10(&self) -> Hsla {
        self.step(ColorScaleStep::TEN)
    }

    /// `Step 11` - Used for text and icons requiring low contrast or less emphasis.
    #[inline]
    pub fn step_11(&self) -> Hsla {
        self.step(ColorScaleStep::ELEVEN)
    }

    /// `Step 12` - Used for text and icons requiring high contrast or prominence.
    #[inline]
    pub fn step_12(&self) -> Hsla {
        self.step(ColorScaleStep::TWELVE)
    }
```

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- N/A

[[PR Description]]

- Adds `StyledExt` for Zed-specific methods like `ui_text`, `v_flex`,
etc.
- Updates components previously using `text_*` methods.

Release Notes:

- N/A

Co-Authored-By: Marshall Bowers <1486634+maxdeviant@users.noreply.github.com>

Co-Authored-By: Marshall Bowers <1486634+maxdeviant@users.noreply.github.com>

This PR switches us over to a fork of `ctor` that contains the fixes
from https://github.com/mmastrac/rust-ctor/pull/295, backported to our
current version of `ctor` (v0.1.20).

Once 1) the `ctor` maintainer publishes a new version with that change
and 2) we're ready to upgrade to the latest version of `ctor` we can
switch back to the mainline version.

Release Notes:

- N/A

Co-Authored-By: Marshall Bowers <1486634+maxdeviant@users.noreply.github.com>

TODO:
- [x] GPUI2: Implement record_backtrace on executor
- [x] GPUI2: Implement rng on executor
- [x] GPUI2: Determine whether to Implement global notifications for
removals
- [x] Get existing tests passing

TODO later:
- [ ] Port: collab_ui and uncomment tests
- [ ] Port: editor and uncomment tests
- [ ] Port: notifications and uncomment tests



Release Notes:

- N/A