added checkExpr in Java

doc/runtime-api.html

@@ -929,7 +929,7 @@ Prelude PGF2> print e'
 AdjCN (PositA red_A) (UseN theatre_N)
 </pre>
 <pre class="java">
-Expr new_e = gr.checkExpr(e,Type.readType("CN")); //// TODO
+Expr new_e = gr.checkExpr(e,Type.readType("CN"));
 System.out.println(e)
 </pre>
 <pre class="csharp">