docs: Implicit multi-arg support for builder params?

[polarathene]

The crates.io docs don't touch on this example, but I see methods that have more than a single arg supported:

buildstructor/examples/collections.rs

Lines 27 to 38 in ae0a5a4

	fn main() {
	let collections = Collections::builder()
	.name("Nandor".to_string())
	.name("Nandor")
	.name("Colin".to_string())
	.names(HashSet::from(["Nadja", "Laszlo"].map(str::to_string)))
	.age("Nandor".to_string(), 0)
	.age("Nandor", 759)
	.age("Colin".to_string(), 100)
	.ages(HashMap::from(
	[("Nadja", 650), ("Laszlo", 364)].map(|(k, v)| (k.to_string(), v)),
	))

Is this due to something with the generics, or specific to the collections (and specific types listed)?

---

Can buildstructor support that same feature on a non-collection type?:

// Either of these?
struct Pair<X, Y>(X, Y);
struct Pair<T>(T, T);

// fn new(pair: Pair<String, String>) -> Self
builder().pair("hello", "world")

Or are you restricted to a tuple input vs separate explicit args?:

// Manual construction of `Pair` type required:
builder().pair(("hello", "world"));
builder().pair_x("hello").pair_y("world").build();

// Awkward via separate builder:
builder().pair(
    Pair::builder().x("hello").y("world").build()
).build();

[BrynCooke]

It's simply down to the naming of the types of the fields:

Special Vec, Deque, Heap, Set, Map support. Add single or multiple items.

I agree it's not explicit in the docs and it could be improved.

Pair support could be added using the same technique.