Document the Inspect event in the service protocol.

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 d824d4dddbdec56724f9f1c43acd48b7b9e55407..e71169d8334b1d9582eb1df76d12c68349a63bbc 100644
--- a/runtime/vm/service/service.md
+++ b/runtime/vm/service/service.md
@@ -1134,6 +1134,11 @@ class Event extends Response {
   //
   // This is provided for the WriteEvent event.
   string bytes [optional];
+
+  // The argument passed to dart:developer.inspect.
+  //
+  // This is provided for the Inspect event.
+  @Instance inspectee [optional];
 }
 ```
 
@@ -1196,7 +1201,10 @@ enum EventKind {
   GC,
 
   // Notification of bytes written, for example, to stdout/stderr.
-  WriteEvent
+  WriteEvent,
+
+  // Notification from dart:developer.inspect.
+  Inspect
 }
 ```