# Objective

Support more kinds of system params in buildable systems, such as a
`ParamSet` or `Vec` containing buildable params or tuples of buildable
params.

## Solution

Replace the `BuildableSystemParam` trait with `SystemParamBuilder` to
make it easier to compose builders. Provide implementations for existing
buildable params, plus tuples, `ParamSet`, and `Vec`.

## Examples

```rust
// ParamSet of tuple: 
let system = (ParamSetBuilder((
    QueryParamBuilder::new(|builder| { builder.with::<B>(); }),
    QueryParamBuilder::new(|builder| { builder.with::<C>(); }),
)),)
    .build_state(&mut world)
    .build_system(|mut params: ParamSet<(Query<&mut A>, Query<&mut A>)>| {
        params.p0().iter().count() + params.p1().iter().count()
    });
	
// ParamSet of Vec:
let system = (ParamSetBuilder(vec![
    QueryParamBuilder::new_box(|builder| { builder.with::<B>(); }),
    QueryParamBuilder::new_box(|builder| { builder.with::<C>(); }),
]),)
    .build_state(&mut world)
    .build_system(|mut params: ParamSet<Vec<Query<&mut A>>>| {
        let mut count = 0;
        params.for_each(|mut query| count += query.iter_mut().count());
        count
    });
```

## Migration Guide

The API for `SystemBuilder` has changed. Instead of constructing a
builder with a world and then adding params, you first create a tuple of
param builders and then supply the world.

```rust
// Before
let system = SystemBuilder::<()>::new(&mut world)
    .local::<u64>()
    .builder::<Local<u64>>(|x| *x = 10)
    .builder::<Query<&A>>(|builder| { builder.with::<B>(); })
    .build(system);

// After
let system = (
    ParamBuilder,
    LocalBuilder(10),
    QueryParamBuilder::new(|builder| { builder.with::<B>(); }),
)
    .build_state(&mut world)
    .build_system(system);
```

## Possible Future Work

Here are a few possible follow-up changes. I coded them up to prove that
this API can support them, but they aren't necessary for this PR.

* chescock#1
* chescock#2
* chescock#3

…res. (bevyengine#17887)

Fixes bevyengine#17290.
<details>
  <summary>Compilation errors before fix</summary>

`cargo clippy --tests --all-features --package bevy_image`:
```rust
error[E0061]: this function takes 7 arguments but 6 arguments were supplied
   --> crates/bevy_core_pipeline/src/tonemapping/mod.rs:451:5
    |
451 |     Image::from_buffer(
    |     ^^^^^^^^^^^^^^^^^^
...
454 |         bytes,
    |         ----- argument #1 of type `std::string::String` is missing
    |
note: associated function defined here
   --> /Users/josiahnelson/Desktop/Programming/Rust/bevy/crates/bevy_image/src/image.rs:930:12
    |
930 |     pub fn from_buffer(
    |            ^^^^^^^^^^^
help: provide the argument
    |
451 |     Image::from_buffer(/* std::string::String */, bytes, image_type, CompressedImageFormats::NONE, false, image_sampler, RenderAssetUsages::RENDER_WORLD)
    |                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
`cargo clippy --tests --all-features --package bevy_gltf`:
```rust
error[E0560]: struct `bevy_pbr::StandardMaterial` has no field named `specular_channel`
    --> crates/bevy_gltf/src/loader.rs:1343:13
     |
1343 |             specular_channel: specular.specular_channel,
     |             ^^^^^^^^^^^^^^^^ `bevy_pbr::StandardMaterial` does not have this field
     |
     = note: available fields are: `emissive_exposure_weight`, `diffuse_transmission`, `diffuse_transmission_channel`, `diffuse_transmission_texture`, `flip_normal_map_y` ... and 9 others

error[E0560]: struct `bevy_pbr::StandardMaterial` has no field named `specular_texture`
    --> crates/bevy_gltf/src/loader.rs:1345:13
     |
1345 |             specular_texture: specular.specular_texture,
     |             ^^^^^^^^^^^^^^^^ `bevy_pbr::StandardMaterial` does not have this field
     |
     = note: available fields are: `emissive_exposure_weight`, `diffuse_transmission`, `diffuse_transmission_channel`, `diffuse_transmission_texture`, `flip_normal_map_y` ... and 9 others

error[E0560]: struct `bevy_pbr::StandardMaterial` has no field named `specular_tint_channel`
    --> crates/bevy_gltf/src/loader.rs:1351:13
     |
1351 |             specular_tint_channel: specular.specular_color_channel,
     |             ^^^^^^^^^^^^^^^^^^^^^ `bevy_pbr::StandardMaterial` does not have this field
     |
     = note: available fields are: `emissive_exposure_weight`, `diffuse_transmission`, `diffuse_transmission_channel`, `diffuse_transmission_texture`, `flip_normal_map_y` ... and 9 others

error[E0560]: struct `bevy_pbr::StandardMaterial` has no field named `specular_tint_texture`
    --> crates/bevy_gltf/src/loader.rs:1353:13
     |
1353 |             specular_tint_texture: specular.specular_color_texture,
     |             ^^^^^^^^^^^^^^^^^^^^^ `bevy_pbr::StandardMaterial` does not have this field
     |
     = note: available fields are: `emissive_exposure_weight`, `diffuse_transmission`, `diffuse_transmission_channel`, `diffuse_transmission_texture`, `flip_normal_map_y` ... and 9 others
```
</details>