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..bcd358d459435d51f7be5bff190f30128393c14f 100644
--- a/runtime/vm/service/service.md
+++ b/runtime/vm/service/service.md
@@ -1464,7 +1464,7 @@ class Instance extends Object {
   //
   // Provided for instance kinds:
   //   List
-  @Instance|Sentinel[] elements [optional];
+  @Instance[]|Sentinel[] elements [optional];

[turnidge, 2015/10/12 16:51:19]

This would mean that we either return a vector of Instances or a vector of
Sentinel.  Neither of those is quite right.

What we are really returning is:

  (@Instance|Sentinel)[]

[Cutch, 2015/10/12 17:40:47]

Done.

 
   // The elements of a List instance.
   //
@@ -2136,6 +2136,15 @@ 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;