Move help menu to canonical F1 binding (#5510)

Currently the fully fledged help menu is bound to `Ctrl-Q`.
Help is widely associated with `F1`.

Before merging check that it is passed through on all platforms and
terminal emulators

crates/nu-cli/src/reedline_config.rs

@@ -524,8 +524,8 @@ fn add_menu_keybindings(keybindings: &mut Keybindings) {
 
     // Help menu keybinding
     keybindings.add_binding(
-        KeyModifiers::CONTROL,
-        KeyCode::Char('q'),
+        KeyModifiers::NONE,
+        KeyCode::F(1),
         ReedlineEvent::Menu("help_menu".to_string()),
     );
 }