Add some macOS emacs keybindings (#1243)

Move cursor left: ^B
    Move cursor right: ^F
    Beginning of line: ^A
    End of line: ^E
    Line up: ^P
    Line down: ^N

CHANGELOG.md

@@ -8,6 +8,7 @@ NOTE: [`epaint`](epaint/CHANGELOG.md), [`eframe`](eframe/CHANGELOG.md), [`egui_w
 ## Unreleased
 
 ### Added ⭐
+* Support a subset of macOS' emacs input field keybindings in `TextEdit` ([#1243](https://github.com/emilk/egui/pull/1243).
 * Much improved font selection ([#1154](https://github.com/emilk/egui/pull/1154)):
   * You can now select any font size and family using `RichText::size` amd `RichText::family` and the new `FontId`.
   * Easily change text styles with `Style::text_styles`.

egui/src/widgets/text_edit/builder.rs

@@ -1092,11 +1092,31 @@ fn on_key_press(
             None
         }
 
+        Key::P | Key::N | Key::B | Key::F | Key::A | Key::E
+            if cfg!(target_os = "macos") && modifiers.ctrl && !modifiers.shift =>
+        {
+            move_single_cursor(&mut cursor_range.primary, galley, key, modifiers);
+            cursor_range.secondary = cursor_range.primary;
+            None
+        }
+
         _ => None,
     }
 }
 
 fn move_single_cursor(cursor: &mut Cursor, galley: &Galley, key: Key, modifiers: &Modifiers) {
+    if cfg!(target_os = "macos") && modifiers.ctrl && !modifiers.shift {
+        match key {
+            Key::A => *cursor = galley.cursor_begin_of_row(cursor),
+            Key::E => *cursor = galley.cursor_end_of_row(cursor),
+            Key::P => *cursor = galley.cursor_up_one_row(cursor),
+            Key::N => *cursor = galley.cursor_down_one_row(cursor),
+            Key::B => *cursor = galley.cursor_left_one_character(cursor),
+            Key::F => *cursor = galley.cursor_right_one_character(cursor),
+            _ => (),
+        }
+        return;
+    }
     match key {
         Key::ArrowLeft => {
             if modifiers.alt || modifiers.ctrl {