Fix two bugs in the serivce protocol specification

runtime/vm/service/service.md

Index: runtime/vm/service/service.md
diff --git a/runtime/vm/service/service.md b/runtime/vm/service/service.md
index 1702ec9b97aa8cd165256f85f1a2c77b01d4f712..5a2d0e0a499bc2acc6640ab45488663bc11e64ad 100644
--- a/runtime/vm/service/service.md
+++ b/runtime/vm/service/service.md
@@ -769,6 +769,13 @@ a vertical bar:
   PropertyType1|PropertyType2 complexProperty;
 ```
 
+We also allow parenthesis on type expressions.  This is useful when a property
+is an _Array_ of multiple independent types:
+
+```
+  (PropertyType1|PropertyType2)[]
+```
+
 When a string is only permitted to take one of a certain set of values,
 we indicate this by the use of the _enum_ format:
 
@@ -1464,7 +1471,7 @@ class Instance extends Object {
   //
   // Provided for instance kinds:
   //   List
-  @Instance|Sentinel[] elements [optional];
+  (@Instance|Sentinel)[] elements [optional];
 
   // The elements of a List instance.
   //
@@ -2136,6 +2143,15 @@ See [Versioning](#versioning).
 ### VM
 
 ```
+class @VM extends Response {
+  // A name identifying this vm. Not guaranteed to be unique.
+  string name;
+}
+```
+
+_@VM_ is a reference to a _VM_ object.
+
+```
 class VM extends Response {
   // Word length on target architecture (e.g. 32, 64).
   int architectureBits;