Eliminate GPUI View, ViewContext, and WindowContext types (#22632)

There's still a bit more work to do on this, but this PR is compiling
(with warnings) after eliminating the key types. When the tasks below
are complete, this will be the new narrative for GPUI:

- `Entity<T>` - This replaces `View<T>`/`Model<T>`. It represents a unit
of state, and if `T` implements `Render`, then `Entity<T>` implements
`Element`.
- `&mut App` This replaces `AppContext` and represents the app.
- `&mut Context<T>` This replaces `ModelContext` and derefs to `App`. It
is provided by the framework when updating an entity.
- `&mut Window` Broken out of `&mut WindowContext` which no longer
exists. Every method that once took `&mut WindowContext` now takes `&mut
Window, &mut App` and every method that took `&mut ViewContext<T>` now
takes `&mut Window, &mut Context<T>`

Not pictured here are the two other failed attempts. It's been quite a
month!

Tasks:

- [x] Remove `View`, `ViewContext`, `WindowContext` and thread through
`Window`
- [x] [@cole-miller @mikayla-maki] Redraw window when entities change
- [x] [@cole-miller @mikayla-maki] Get examples and Zed running
- [x] [@cole-miller @mikayla-maki] Fix Zed rendering
- [x] [@mikayla-maki] Fix todo! macros and comments
- [x] Fix a bug where the editor would not be redrawn because of view
caching
- [x] remove publicness window.notify() and replace with
`AppContext::notify`
- [x] remove `observe_new_window_models`, replace with
`observe_new_models` with an optional window
- [x] Fix a bug where the project panel would not be redrawn because of
the wrong refresh() call being used
- [x] Fix the tests
- [x] Fix warnings by eliminating `Window` params or using `_`
- [x] Fix conflicts
- [x] Simplify generic code where possible
- [x] Rename types
- [ ] Update docs

### issues post merge

- [x] Issues switching between normal and insert mode
- [x] Assistant re-rendering failure
- [x] Vim test failures
- [x] Mac build issue



Release Notes:

- N/A

---------

Co-authored-by: Antonio Scandurra <me@as-cii.com>
Co-authored-by: Cole Miller <cole@zed.dev>
Co-authored-by: Mikayla <mikayla@zed.dev>
Co-authored-by: Joseph <joseph@zed.dev>
Co-authored-by: max <max@zed.dev>
Co-authored-by: Michael Sloan <michael@zed.dev>
Co-authored-by: Mikayla Maki <mikaylamaki@Mikaylas-MacBook-Pro.local>
Co-authored-by: Mikayla <mikayla.c.maki@gmail.com>
Co-authored-by: joão <joao@zed.dev>

crates/assistant_slash_commands/src/tab_command.rs

@@ -1,4 +1,4 @@
-use anyhow::{Context, Result};
+use anyhow::{Context as _, Result};
 use assistant_slash_command::{
     ArgumentCompletion, SlashCommand, SlashCommandOutput, SlashCommandOutputSection,
     SlashCommandResult,
@@ -6,13 +6,13 @@ use assistant_slash_command::{
 use collections::{HashMap, HashSet};
 use editor::Editor;
 use futures::future::join_all;
-use gpui::{Entity, Task, WeakView};
+use gpui::{Task, WeakEntity};
 use language::{BufferSnapshot, CodeLabel, HighlightId, LspAdapterDelegate};
 use std::{
     path::PathBuf,
     sync::{atomic::AtomicBool, Arc},
 };
-use ui::{prelude::*, ActiveTheme, WindowContext};
+use ui::{prelude::*, ActiveTheme, App, Window};
 use util::ResultExt;
 use workspace::Workspace;
 
@@ -51,8 +51,9 @@ impl SlashCommand for TabSlashCommand {
         self: Arc<Self>,
         arguments: &[String],
         cancel: Arc<AtomicBool>,
-        workspace: Option<WeakView<Workspace>>,
-        cx: &mut WindowContext,
+        workspace: Option<WeakEntity<Workspace>>,
+        window: &mut Window,
+        cx: &mut App,
     ) -> Task<Result<Vec<ArgumentCompletion>>> {
         let mut has_all_tabs_completion_item = false;
         let argument_set = arguments
@@ -82,10 +83,10 @@ impl SlashCommand for TabSlashCommand {
         });
         let current_query = arguments.last().cloned().unwrap_or_default();
         let tab_items_search =
-            tab_items_for_queries(workspace, &[current_query], cancel, false, cx);
+            tab_items_for_queries(workspace, &[current_query], cancel, false, window, cx);
 
         let comment_id = cx.theme().syntax().highlight_id("comment").map(HighlightId);
-        cx.spawn(|_| async move {
+        window.spawn(cx, |_| async move {
             let tab_items = tab_items_search.await?;
             let run_command = tab_items.len() == 1;
             let tab_completion_items = tab_items.into_iter().filter_map(|(path, ..)| {
@@ -137,15 +138,17 @@ impl SlashCommand for TabSlashCommand {
         arguments: &[String],
         _context_slash_command_output_sections: &[SlashCommandOutputSection<language::Anchor>],
         _context_buffer: BufferSnapshot,
-        workspace: WeakView<Workspace>,
+        workspace: WeakEntity<Workspace>,
         _delegate: Option<Arc<dyn LspAdapterDelegate>>,
-        cx: &mut WindowContext,
+        window: &mut Window,
+        cx: &mut App,
     ) -> Task<SlashCommandResult> {
         let tab_items_search = tab_items_for_queries(
             Some(workspace),
             arguments,
             Arc::new(AtomicBool::new(false)),
             true,
+            window,
             cx,
         );
 
@@ -160,15 +163,16 @@ impl SlashCommand for TabSlashCommand {
 }
 
 fn tab_items_for_queries(
-    workspace: Option<WeakView<Workspace>>,
+    workspace: Option<WeakEntity<Workspace>>,
     queries: &[String],
     cancel: Arc<AtomicBool>,
     strict_match: bool,
-    cx: &mut WindowContext,
+    window: &mut Window,
+    cx: &mut App,
 ) -> Task<anyhow::Result<Vec<(Option<PathBuf>, BufferSnapshot, usize)>>> {
     let empty_query = queries.is_empty() || queries.iter().all(|query| query.trim().is_empty());
     let queries = queries.to_owned();
-    cx.spawn(|mut cx| async move {
+    window.spawn(cx, |mut cx| async move {
         let mut open_buffers =
             workspace
                 .context("no workspace")?
@@ -281,7 +285,7 @@ fn tab_items_for_queries(
 
 fn active_item_buffer(
     workspace: &mut Workspace,
-    cx: &mut ViewContext<Workspace>,
+    cx: &mut Context<Workspace>,
 ) -> anyhow::Result<BufferSnapshot> {
     let active_editor = workspace
         .active_item(cx)