add usage with escaped characters

readme.md

@@ -41,6 +41,17 @@ tree.match(matchHelper("input.my-control[type!='radio'][checked], input[value^='
 });
 ```
 
+## Classnames with escaped characters
+
+```js
+var matchHelper = require("posthtml-match-helper");
+
+tree.match(matchHelper("input.\\[display:none\\]"), function (node) {
+	// do stuff with node that matched either of the selectors...
+});
+```
+
+
 ## The helper function
 
 #### Arguments