Fix mistake in README (#471)

README.md

@@ -170,7 +170,7 @@ Certain options can be provided in the `options` object of *any* method that cal
 
 ### Defining custom diffing behaviors
 
-If you need behavior a little different to what any of the text diffing functions above offer, you can roll your own by customizing both the tokenization behavior used and the notion of equality used to determine if two characters are equal.
+If you need behavior a little different to what any of the text diffing functions above offer, you can roll your own by customizing both the tokenization behavior used and the notion of equality used to determine if two tokens are equal.
 
 The simplest way to customize tokenization behavior is to simply tokenize the texts you want to diff yourself, with your own code, then pass the arrays of tokens to `diffArrays`. For instance, if you wanted a semantically-aware diff of some code, you could try tokenizing it using a parser specific to the programming language the code is in, then passing the arrays of tokens to `diffArrays`.