Add a Command to trigger observers with statically known components

[ItsDoot]

What problem does this solve or what need does it fill?

Triggering Observers with specific components currently requires you to know the component's ComponentId, even if the component type is statically known. This generally results in needing to store all necessary ComponentIds in a Resource and grabbing them as needed from it.

What solution would you like?

impl Commands {
    // I would expect the Bundle's component IDs to be chained with the ones provided with the TriggerTargets
    pub fn trigger_targets_with<B: Bundle>(&mut self, event: impl Event, targets: impl TriggerTargets);
}

What alternative(s) have you considered?

My current situation:

fn system(commands: Commands, actions: Res<ActionIds>) {
    let entity = Entity::PLACEHOLDER;
    commands.trigger_targets(ActionFinished(actions.drink), TargetedAction(entity, actions.drink));
}

#[derive(Resource)]
pub struct ActionIds {
    drink: ComponentId,
    idle: ComponentId,
}

impl FromWorld for ActionIds {
    fn from_world(world: &mut World) -> Self {
        Self {
            drink: world.init_component::<Drink>(),
            idle: world.init_component::<Idle>(),
        }
    }
}

struct TargetedAction(Entity, ComponentId);

impl TriggerTargets for TargetedAction {
    fn components(&self) -> impl ExactSizeIterator<Item = ComponentId> {
        std::iter::once(self.1)
    }
    fn entities(&self) -> impl ExactSizeIterator<Item = Entity> {
        std::iter::once(self.0)
    }
}

Additional context

Originally brought up on discord.