refactor(token-predicate): simplify negate function (#153)

Author: MichaelDeBoey

src/token-predicate.mjs

@@ -1,19 +1,10 @@
-/**
- * Negate the result of `this` calling.
- * @param {Token} token The token to check.
- * @returns {boolean} `true` if the result of `this(token)` is `false`.
- */
-function negate0(token) {
-    return !this(token) //eslint-disable-line no-invalid-this
-}
-
 /**
  * Creates the negate function of the given function.
  * @param {function(Token):boolean} f - The function to negate.
  * @returns {function(Token):boolean} Negated function.
  */
 function negate(f) {
-    return negate0.bind(f)
+    return (token) => !f(token)
 }
 
 /**