Readme update for character offset

Author: pejrak

readme.md

@@ -135,10 +135,10 @@ reactStringReplace('hey hey you', /(hey)/g, () => <span>hey</span>);
 
 Type: `function`
 
-The replacer function to run each time `match` is found. This function will be patched the matching string and an index which can be used for adding keys to replacement components if necessary.
+The replacer function to run each time `match` is found. This function will be patched the matching string and an `index` which can be used for adding keys to replacement components if necessary. Character `offset` identifies the position of match start in the provided text.
 
 ```js
-const func = (match, index) => <span key={index}>{match}</span>;
+const func = (match, index, offset) => <span key={index}>{match}</span>;
 reactStringReplace('hey hey you', /(hey)/g, func);
 ```