On macOS, add documentEdited APIs (#2550)

* On macOS, add documentEdited APIs

Port of 33fdeab629

* Update src/platform/macos.rs

Co-authored-by: Mads Marquart <mads@marquart.dk>

* typo

Co-authored-by: Mads Marquart <mads@marquart.dk>

src/platform/macos.rs

@@ -36,6 +36,25 @@ pub trait WindowExtMacOS {
 
     /// Sets whether or not the window has shadow.
     fn set_has_shadow(&self, has_shadow: bool);
+
+    /// Get the window's edit state.
+    ///
+    /// # Examples
+    ///
+    /// ```ignore
+    /// WindowEvent::CloseRequested => {
+    ///     if window.is_document_edited() {
+    ///         // Show the user a save pop-up or similar
+    ///     } else {
+    ///         // Close the window
+    ///         drop(window);
+    ///     }
+    /// }
+    /// ```
+    fn is_document_edited(&self) -> bool;
+
+    /// Put the window in a state which indicates a file save is required.
+    fn set_document_edited(&self, edited: bool);
 }
 
 impl WindowExtMacOS for Window {
@@ -68,6 +87,16 @@ impl WindowExtMacOS for Window {
     fn set_has_shadow(&self, has_shadow: bool) {
         self.window.set_has_shadow(has_shadow)
     }
+
+    #[inline]
+    fn is_document_edited(&self) -> bool {
+        self.window.is_document_edited()
+    }
+
+    #[inline]
+    fn set_document_edited(&self, edited: bool) {
+        self.window.set_document_edited(edited)
+    }
 }
 
 /// Corresponds to `NSApplicationActivationPolicy`.