Hash implementation does not match Equals implementation

[fabianfett]

The hash implementation does not match the equals implementation.

See this test case

swift-http-types/Tests/HTTPTypesTests/HTTPTypesTests.swift

Lines 142 to 162 in 4b1dd0c

	@Test func hashMatchesEqualityForDifferentOrder() {
	let fields1: HTTPFields = [
	.acceptEncoding: "br",
	.acceptEncoding: "gzip",
	.accept: "*/*",
	]
	// Fields with differently named fields in a different order are equal, since the
	// relative order of same-named fields is preserved.
	let fields2: HTTPFields = [
	.acceptEncoding: "br",
	.accept: "*/*",
	.acceptEncoding: "gzip",
	]
	#expect(fields1 == fields2)
	// Equal values must therefore hash equally.
	withKnownIssue("HTTPFields.hash(into:) is order sensitive while == is not") {
	#expect(fields1.hashValue == fields2.hashValue)
	}
	}