Added optional semicolon at the end of RPC elements that contain options.

com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext

diff --git a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext
index cb3b184..18637c3 100644
--- a/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext
+++ b/com.google.eclipse.protobuf/src/com/google/eclipse/protobuf/Protobuf.xtext
@@ -143,7 +143,7 @@
 
 Rpc: 
   'rpc' name=ID  '(' argType=MessageReference ')' 'returns' '(' returnType=MessageReference ')' 
-  (('{' options+=Option* '}') | ';')
+  (('{' options+=Option* '}')(';')? | ';')
 ;
 
 MessageReference: