docs(README.closure.md): clarify sentence

Closes angular#11979

Author: petebacondarwin

README.closure.md

@@ -1,8 +1,8 @@
 Using AngularJS with the Closure Compiler
 =========================================
 
-The Closure Compiler project contains externs definitions for AngularJS
-JavaScript in its `contrib/externs` directory.
+The Closure Compiler project contains definitions for the AngularJS JavaScript
+in its `contrib/externs` directory.
 
 The definitions contain externs for use with the Closure compiler (aka
 JSCompiler). Passing these files to the --externs parameter of a compiler