simplify PEG sentence

Author: bfulton

README.md

@@ -8,9 +8,8 @@ This project ports some ideas [Russ Cox](http://swtch.com/~rsc/) shared on
 [how Google Code Search works](http://swtch.com/~rsc/regexp/regexp4.html) — in
 particular the [`RegexpQuery` and related functions](https://code.google.com/p/codesearch/source/browse/index/regexp.go) —
 from Go to JavaScript. Since JavaScript doesn't have an equivalent to Go's [`regexp/syntax`](http://golang.org/pkg/regexp/syntax/),
-we also use [PEG.js](http://pegjs.majda.cz/) to introduce a simplified regular
-expression grammar to obtain parse trees for a subset of valid [`RegExp`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp)
-patterns.
+use [PEG.js](http://pegjs.majda.cz/) to introduce a simplified regular
+expression grammar and obtain a parse tree.
 
 The goal is to query trigram indexes from JS clients.