[cleanup] While reading the code: fix up some comments in module_state.fidl.

These reference outdated method names, and another method was missing.

TEST=none

Change-Id: Ica21707ae4326e0e8f0e17fd1e00bc2880ccd302
diff --git a/public/fidl/fuchsia.modular/module/module_state.fidl b/public/fidl/fuchsia.modular/module/module_state.fidl
index a35bab0..f2934c9 100644
--- a/public/fidl/fuchsia.modular/module/module_state.fidl
+++ b/public/fidl/fuchsia.modular/module/module_state.fidl
@@ -13,7 +13,8 @@
 /// Currently possible state transitions (and the events that cause
 /// them) are:
 ///
-///            -> RUNNING     ModuleContext.StartModule() or
+///            -> RUNNING     ModuleContext.AddModuleToStory() or
+///                           ModuleContext.EmbedModule() or
 ///                           StoryController.AddModule()
 ///   RUNNING  -> STOPPED     ModuleController.Stop() or StoryController.Stop()
 ///   RUNNING  -> ERROR       application exits