Add Generics Section (#33367)

* Add Generics Section

* fix: added front matter block

guide/english/swift/generics/index.md

@@ -0,0 +1,46 @@
+---
+title: Generics
+---
+
+# Generics
+
+Write a name inside angle brackets to make a generic function or type.
+```Swift
+func makeArray<Item>(repeating item: Item, numberOfTimes: Int) -> [Item] {
+	var result = [Item]()
+	for _ in 0..<numberOfTimes {
+		result.append(item)
+	}
+	return result
+}
+makeArray(repeating: "knock", numberOfTimes: 4)
+```
+
+***You can make generic forms of functions and methods, as well as classes, enumerations, and structures.***
+
+```Swift
+// Reimplement the Swift standard library's optional type
+	enum OptionalValue<Wrapped> {
+		case none
+		case some(Wrapped)
+	}
+	var possibleInteger: OptionalValue<Int> = .none
+	possibleInteger = .some(100)
+```
+
+Use  `where`  right before the body to specify a list of requirements—for example, to require the type to implement a protocol, to require two types to be the same, or to require a class to have a particular superclass.
+
+```swift
+func anyCommonElements<T: Sequence, U: Sequence>(_ lhs: T, _ rhs: U) -> Bool
+where T.Element: Equatable, T.Element == U.Element
+{
+	for lhsItem in lhs {
+		for rhsItem in rhs {
+			if lhsItem == rhsItem {
+			return true
+			}
+		}
+	}
+return false
+}
+anyCommonElements([1, 2, 3], [3])