Kotlin type aliases (#31846)

* Kotlin type aliases

* fix/folder-name

guide/english/kotlin/type-aliases/index.md

@@ -0,0 +1,32 @@
+---
+title: Type Aliases
+---
+
+# Type Aliases
+
+A type alias is a way to provide an alternative name to an existing type. This can be helpful when an existing type has a long name. It's important to note, Type aliases do not introduce new types. They still equate to their original, underlying types.
+
+### Basic Usage
+
+```kotlin
+typealias LocalUsers = List<User.LocalUser>
+```
+
+You can also create type aliases for function types.
+
+```kotlin
+typealias ValidUsername = (String) -> Boolean
+```
+
+And for inner & nested classes.
+```kotlin
+class Foo {
+    inner class Bar
+}
+class Baz {
+    inner class Bar
+}
+
+typealias FBar = Foo.Bar
+typealias BBar = Baz.Bar
+```