docs(glossary): improve DI word

public/docs/ts/latest/glossary.jade

@@ -248,7 +248,7 @@ include _util-fns
     to assemble and run applications by "injecting" application parts
     into other application parts where and when needed.
 
-    At the core is an [`Injector`](#injector) that returns dependency values on request.
+    At the core there is an [`Injector`](#injector) that returns dependency values on request.
     The expression `injector.get(token)` returns the value associated with the given token.
 
     A token is an Angular type (`OpaqueToken`). We rarely deal with tokens directly; most