Make HermesRuntime::description() always include "HermesRuntime"

Summary:
If name is passed in as part of RuntimeConfig, that is included
in the description, too.
Changelog: [Internal]

Reviewed By: dulinriley

Differential Revision: D20716320

fbshipit-source-id: f2fba6df32f496090dee787d8b7f55a6a4dd8ed8

ReactCommon/jsi/jsi/jsi.h

@@ -188,9 +188,10 @@ class Runtime {
   /// \return the global object
   virtual Object global() = 0;
 
-  /// \return a short printable description of the instance.  This
-  /// should only be used by logging, debugging, and other
-  /// developer-facing callers.
+  /// \return a short printable description of the instance.  It should
+  /// at least include some human-readable indication of the runtime
+  /// implementation.  This should only be used by logging, debugging,
+  /// and other developer-facing callers.
   virtual std::string description() = 0;
 
   /// \return whether or not the underlying runtime supports debugging via the