Use alt-z to toggle soft wrap in active editor

When there isn't a default soft-wrapping for the active editor, we
will soft wrap at the editor width. This is consistent with Visual
Studio Code.

assets/keymaps/default.json

@@ -164,6 +164,7 @@
         "bindings": {
             "enter": "editor::Newline",
             "cmd-enter": "editor::NewlineBelow",
+            "alt-z": "editor::ToggleSoftWrap",
             "cmd-f": [
                 "buffer_search::Deploy",
                 {

crates/editor/src/editor.rs

@@ -236,6 +236,7 @@ actions!(
         RestartLanguageServer,
         Hover,
         Format,
+        ToggleSoftWrap
     ]
 );
 
@@ -346,6 +347,7 @@ pub fn init(cx: &mut MutableAppContext) {
     cx.add_action(Editor::toggle_code_actions);
     cx.add_action(Editor::open_excerpts);
     cx.add_action(Editor::jump);
+    cx.add_action(Editor::toggle_soft_wrap);
     cx.add_async_action(Editor::format);
     cx.add_action(Editor::restart_language_server);
     cx.add_action(Editor::show_character_palette);
@@ -5812,6 +5814,19 @@ impl Editor {
             .update(cx, |map, cx| map.set_wrap_width(width, cx))
     }
 
+    pub fn toggle_soft_wrap(&mut self, _: &ToggleSoftWrap, cx: &mut ViewContext<Self>) {
+        if self.soft_wrap_mode_override.is_some() {
+            self.soft_wrap_mode_override.take();
+        } else {
+            let soft_wrap = match self.soft_wrap_mode(cx) {
+                SoftWrap::None => settings::SoftWrap::EditorWidth,
+                SoftWrap::EditorWidth | SoftWrap::Column(_) => settings::SoftWrap::None,
+            };
+            self.soft_wrap_mode_override = Some(soft_wrap);
+        }
+        cx.notify();
+    }
+
     pub fn highlight_rows(&mut self, rows: Option<Range<u32>>) {
         self.highlighted_rows = rows;
     }