Standard library documentation continued.

core/builtins/native/kotlin/String.kt

@@ -21,8 +21,14 @@ package kotlin
  * implemented as instances of this class.
  */
 public class String : Comparable<String>, CharSequence {
+    /**
+     * Returns a string obtained by concatenating this string with the string representation of the given [other] object.
+     */
     public fun plus(other: Any?): String
 
+    /**
+     * Returns the character at the specified [index].
+     */
     public fun get(index: Int): Char
 
     public override fun length(): Int