Add workspace::ToggleEditPrediction for toggling inline completions globally (#35418)

Closes: https://github.com/zed-industries/zed/issues/23704

Existing action is `editor::ToggleEditPrediction` ("This Buffer").
This action is `workspace::ToggleEditPredction` ("All Files").

You can add a custom keybind wi shortcut with:
```json
  { "context": "Workspace", "bindings": { "ctrl-alt-cmd-e": "workspace::ToggleEditPrediction" } },
```

<img width="212" height="439" alt="Screenshot 2025-07-31 at 12 52 19"
src="https://github.com/user-attachments/assets/15879daa-7d4d-4308-ab2b-5e78507f2fa5"
/>


Release Notes:

- Added `workspace::ToggleEditPrediction` action for toggling
`show_edit_predictions` in settings (Edit Predictions menu -> All
Files).

crates/workspace/src/workspace.rs

@@ -48,7 +48,10 @@ pub use item::{
     ProjectItem, SerializableItem, SerializableItemHandle, WeakItemHandle,
 };
 use itertools::Itertools;
-use language::{Buffer, LanguageRegistry, Rope};
+use language::{
+    Buffer, LanguageRegistry, Rope,
+    language_settings::{AllLanguageSettings, all_language_settings},
+};
 pub use modal_layer::*;
 use node_runtime::NodeRuntime;
 use notifications::{
@@ -74,7 +77,7 @@ use remote::{SshClientDelegate, SshConnectionOptions, ssh_session::ConnectionIde
 use schemars::JsonSchema;
 use serde::Deserialize;
 use session::AppSession;
-use settings::Settings;
+use settings::{Settings, update_settings_file};
 use shared_screen::SharedScreen;
 use sqlez::{
     bindable::{Bind, Column, StaticColumnCount},
@@ -233,6 +236,8 @@ actions!(
         ToggleBottomDock,
         /// Toggles centered layout mode.
         ToggleCenteredLayout,
+        /// Toggles edit prediction feature globally for all files.
+        ToggleEditPrediction,
         /// Toggles the left dock.
         ToggleLeftDock,
         /// Toggles the right dock.
@@ -5546,6 +5551,7 @@ impl Workspace {
             .on_action(cx.listener(Self::activate_pane_at_index))
             .on_action(cx.listener(Self::move_item_to_pane_at_index))
             .on_action(cx.listener(Self::move_focused_panel_to_next_position))
+            .on_action(cx.listener(Self::toggle_edit_predictions_all_files))
             .on_action(cx.listener(|workspace, _: &Unfollow, window, cx| {
                 let pane = workspace.active_pane().clone();
                 workspace.unfollow_in_pane(&pane, window, cx);
@@ -5977,6 +5983,19 @@ impl Workspace {
             }
         });
     }
+
+    fn toggle_edit_predictions_all_files(
+        &mut self,
+        _: &ToggleEditPrediction,
+        _window: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
+        let fs = self.project().read(cx).fs().clone();
+        let show_edit_predictions = all_language_settings(None, cx).show_edit_predictions(None, cx);
+        update_settings_file::<AllLanguageSettings>(fs, cx, move |file, _| {
+            file.defaults.show_edit_predictions = Some(!show_edit_predictions)
+        });
+    }
 }
 
 fn leader_border_for_pane(