Document that array constructor throws RuntimeException on negative size

generators/builtins/arrays.kt

@@ -35,6 +35,7 @@ class GenerateArrays(out: PrintWriter) : BuiltInsSourceGenerator(out) {
             out.println("/**")
             out.println(" * An array of ${typeLower}s. When targeting the JVM, instances of this class are represented as `$typeLower[]`.")
             out.println(" * @constructor Creates a new array of the specified [size], with all elements initialized to $defaultValue.")
+            out.println(" * @throws RuntimeException if the specified [size] is negative.")
             out.println(" */")
             out.println("public class ${s}Array(size: Int) {")
             out.println("    /**")
@@ -43,6 +44,8 @@ class GenerateArrays(out: PrintWriter) : BuiltInsSourceGenerator(out) {
             out.println("     *")
             out.println("     * The function [init] is called for each array element sequentially starting from the first one.")
             out.println("     * It should return the value for an array element given its index.")
+            out.println("     *")
+            out.println("     * @throws RuntimeException if the specified [size] is negative.")
             out.println("     */")
             out.println("    public inline constructor(size: Int, init: (Int) -> $s)")
             out.println()