Document usage of some Sequence

Author: x-sheep

README.md

@@ -35,7 +35,7 @@ Example with multiple inputs, and a custom repeat count:
 import Testing
 import PropertyBased
 
-let stringCreator = Gen.letterOrNumber.string(of: Gen.int(in: 1...10))
+let stringCreator: Generator<String, some Sequence> = Gen.letterOrNumber.string(of: 1...10)
 
 @Test func testStringRepeat() async {
   await propertyCheck(count: 500, input: stringCreator, Gen.int(in: 0...5)) { str, n in

Sources/PropertyBased/Generator.swift

@@ -5,6 +5,11 @@
 ///
 /// A Generator contains a specific function that creates new values, as well as a function
 /// that builds a shrinking sequence for any value.
+///
+/// In most cases, the exact type of `ShrinkSequence` doesn't need to be public in your code, and the `some` keyword can be used instead.
+/// ```swift
+/// let gen = Generator<Output, some Sequence> = ...
+/// ```
 public struct Generator<ResultValue, ShrinkSequence: Sequence>: Sendable {
     public typealias InputValue = ShrinkSequence.Element