Temporary add jvm.overloads annotation for generated joinToString() method.

Stdlib generator: allow to specify arbitrary annotations for all or some of generic function expansions.

libraries/tools/kotlin-stdlib-gen/src/templates/Engine.kt

@@ -84,6 +84,7 @@ class GenericFunction(val signature: String, val keyword: String = "fun") : Comp
         override fun onKeySet(key: Family) = include(key)
     }
     val customPrimitiveBodies = HashMap<Pair<Family, PrimitiveType>, String>()
+    val annotations = FamilyProperty<String>()
 
     fun bodyForTypes(family: Family, vararg primitiveTypes: PrimitiveType, b: () -> String) {
         include(family)
@@ -295,6 +296,8 @@ class GenericFunction(val signature: String, val keyword: String = "fun") : Comp
                     ?.let { platformName -> builder.append("platformName(\"${platformName}\")\n")}
         }
 
+        annotations[f]?.let { builder.append(it).append('\n') }
+
         builder.append("public ")
         if (inline[f] == true)
             builder.append("inline ")

libraries/tools/kotlin-stdlib-gen/src/templates/Strings.kt

@@ -63,6 +63,7 @@ fun strings(): List<GenericFunction> {
 
         exclude(Strings)
         returns("String")
+        annotations("kotlin.jvm.overloads", Iterables)
         body {
             """
             return joinTo(StringBuilder(), separator, prefix, postfix, limit, truncated, transform).toString()