**Is your feature request related to a problem? Please describe.**

MenuItem labels are meant to be short. There's currently no place to elaborate/clarify them.

**Describe the solution you'd like**

`NSMenuItem` supports a [`toolTip`](https://developer.apple.com/documentation/appkit/nsmenuitem/1514848-tooltip?language=objc) property. Would be nice if Electron could expose this.

From what I could find, [GTK (Linux) does not have any way to set tooltip on menu items](https://developer.gnome.org/gtk3/stable/GtkMenuItem.html).

No idea about Windows.

**Describe alternatives you've considered**

None.

**Additional context**

No.
shell/browser/ui/atom_menu_model.cc
if (delegate_) {
    return delegate_->ShouldRegisterAcceleratorForCommandId(
        GetCommandIdAt(index));
  }
  return true;
}
bool AtomMenuModel::WorksWhenHiddenAt(int index) const {
  if (delegate_) {
    return delegate_->ShouldCommandIdWorkWhenHidden(GetCommandIdAt(index));
  }
  return true;
}
void AtomMenuModel::MenuWillClose() {
  ui::SimpleMenuModel::MenuWillClose();
  for (Observer& observer : observers_) {
    observer.OnMenuWillClose();
  }
}
void AtomMenuModel::MenuWillShow() {
  ui::SimpleMenuModel::MenuWillShow();
  for (Observer& observer : observers_) {
    observer.OnMenuWillShow();
  }
}
AtomMenuModel* AtomMenuModel::GetSubmenuModelAt(int index) {
  return static_cast<AtomMenuModel*>(
      ui::SimpleMenuModel::GetSubmenuModelAt(index));
}
}