chore: Extract languages from zed crate (#8270)

- Moves languages module from `zed` into a separate crate. That way we
have less of a long pole at the end of compilation.
- Removes moot dependencies on editor/picker. This is totally harmless
and might help in the future if we decide to decouple picker from
editor.

Before:
```
Number of crates that depend on 'picker' but not on 'editor': 1
Total number of crates that depend on 'picker': 13
Total number of crates that depend on 'editor': 30
```
After:
```
Number of crates that depend on 'picker' but not on 'editor': 5
Total number of crates that depend on 'picker': 12
Total number of crates that depend on 'editor': 26
```
The more crates depend on just picker but not editor, the better in that
case.

Release Notes:

- N/A

crates/editor/src/editor.rs

@@ -122,7 +122,7 @@ use ui::{
 };
 use util::{maybe, post_inc, RangeExt, ResultExt, TryFutureExt};
 use workspace::Toast;
-use workspace::{searchable::SearchEvent, ItemNavHistory, Pane, SplitDirection, ViewId, Workspace};
+use workspace::{searchable::SearchEvent, ItemNavHistory, SplitDirection, ViewId, Workspace};
 
 use crate::hover_links::find_url;
 
@@ -356,7 +356,6 @@ type InlayBackgroundHighlight = (fn(&ThemeColors) -> Hsla, Vec<InlayHighlight>);
 ///
 /// See the [module level documentation](self) for more information.
 pub struct Editor {
-    handle: WeakView<Self>,
     focus_handle: FocusHandle,
     /// The text buffer being edited
     buffer: Model<MultiBuffer>,
@@ -1488,7 +1487,6 @@ impl Editor {
         cx.on_blur(&focus_handle, Self::handle_blur).detach();
 
         let mut this = Self {
-            handle: cx.view().downgrade(),
             focus_handle,
             buffer: buffer.clone(),
             display_map: display_map.clone(),
@@ -1686,10 +1684,6 @@ impl Editor {
         self.workspace.as_ref()?.0.upgrade()
     }
 
-    pub fn pane(&self, cx: &AppContext) -> Option<View<Pane>> {
-        self.workspace()?.read(cx).pane_for(&self.handle.upgrade()?)
-    }
-
     pub fn title<'a>(&self, cx: &'a AppContext) -> Cow<'a, str> {
         self.buffer().read(cx).title(cx)
     }