Update README.md

Author: seborama

README.md

@@ -144,7 +144,7 @@ Do not double-quote them, or they will become plain strings!
         * Go classifies bit shift operators with the higher `*`.
         * `&&` is synonymous of `And`.
         * `||` is synonymous of `Or`.
-* Types: String, Number, Bool
+* Types: String, Number, Bool, MultiValue
 * Associativity with parentheses: `(` and `)`
 * Functions:
     * Built-in: pi, cos, floor, sin, sqrt, trunc, and more (see `function.go`: `Eval()`)