Feature/contains iterate by index

[lennon-guan]

Refactor Contains function to improve performance by using index iteration over collection

[lennon-guan]

// Benchmark Code & Result
package lo

import "testing"

func oldContains[T comparable](collection []T, element T) bool {
	for _, item := range collection {
		if item == element {
			return true
		}
	}
	return false
}

type containsTestStruct struct {
	A, B, C, D int
	E, F       string
}

var (
	containsInts    = []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
	containsStrings = []string{"1", "2", "3", "4", "5", "6", "7", "8", "9", "10"}
	containsStructs = []containsTestStruct{{}, {}, {}, {}, {}, {}, {}, {}, {}, {A: 1}}
)

func doBenchmark[T comparable](b *testing.B, collection []T, fn func([]T, T) bool) {
	element := collection[len(collection)-1]
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		fn(collection, element)
	}
}

func BenchmarkOldContainsInt(b *testing.B) {
	doBenchmark(b, containsInts, oldContains[int])
}

func BenchmarkContainsInt(b *testing.B) {
	doBenchmark(b, containsInts, Contains[int])
}

func BenchmarkOldContainsString(b *testing.B) {
	doBenchmark(b, containsStrings, oldContains[string])
}

func BenchmarkContainsString(b *testing.B) {
	doBenchmark(b, containsStrings, Contains[string])
}

func BenchmarkOldContainsStruct(b *testing.B) {
	doBenchmark(b, containsStructs, oldContains[containsTestStruct])
}

func BenchmarkContainsStruct(b *testing.B) {
	doBenchmark(b, containsStructs, Contains[containsTestStruct])
}

//result

goos: windows
goarch: amd64
pkg: github.com/samber/lo
cpu: AMD Ryzen 7 5800H with Radeon Graphics         
BenchmarkOldContainsInt-16       	235373313	         5.196 ns/op	       0 B/op	       0 allocs/op
BenchmarkContainsInt-16          	232900494	         5.139 ns/op	       0 B/op	       0 allocs/op
BenchmarkOldContainsString-16    	127452003	         9.454 ns/op	       0 B/op	       0 allocs/op
BenchmarkContainsString-16       	174648490	         6.784 ns/op	       0 B/op	       0 allocs/op
BenchmarkOldContainsStruct-16    	20864157	        54.47 ns/op	       0 B/op	       0 allocs/op
BenchmarkContainsStruct-16       	26957204	        44.76 ns/op	       0 B/op	       0 allocs/op
PASS
ok  	github.com/samber/lo	10.777s