examples: lang: Update examples

examples/lang/polymorphic-lambda.mcl

@@ -0,0 +1,19 @@
+import "fmt"
+
+$add = func($x) {
+	$x + $x
+}
+
+$num = 2
+$out1 = $add($num) # 4
+
+print fmt.printf("%d + %d is %d", $num, $num, $out1) { # simple math
+	Meta:autogroup => false,
+}
+
+$val = "hello"
+$out2 = $add($val) # hellohello
+
+print fmt.printf("%s + %s is %s", $val, $val, $out2) { # simple concat
+	Meta:autogroup => false,
+}