Update README.md

Author: seborama

README.md

@@ -157,7 +157,7 @@ A function is defined as a Go type: `type FunctionalValue func(...Value) Value`
 
 Function names are case-insensitive.
 
-A function can optionally accept one or more **space-separated** arguments, but it must return a single `Value`.
+A **function** can optionally accept one or more **space-separated arguments**, but it must return a single `Value`.
 
 It should be noted that a `MultiValue` type is available that can hold multiple `Value` elements. A function can use `MultiValue` as its return type to effectively return multiple `Value`'s. Of course, as `MultiValue` is a `Value` type, functions can also accept it as part of their argument(s). Refer to the test `TestMultiValueFunctions`, for an example.