Purge references of "Mojo Application" from comments & var names.

mojo/edk/embedder/README.md

 Mojo Embedder API
 =================
 
 The Mojo Embedder API is an unstable, internal API to the Mojo system
 implementation. It should be used by code running on top of the system-level
 APIs to set up the Mojo environment (instead of directly instantiating things
 from src/mojo/edk/system).
 
-Example uses: Mojo shell, to set up the Mojo environment for Mojo apps; Chromium
-code, to set up the Mojo IPC system for use between processes. Note that most
-code should use the Mojo Public API (under src/mojo/public) instead. The
-Embedder API should only be used to initialize the environment, set up the
+Example uses: Service Manager, to set up the Mojo environment for Services;
+Chromium code, to set up the Mojo IPC system for use between processes. Note
+that most code should use the Mojo Public API (under src/mojo/public) instead.
+The Embedder API should only be used to initialize the environment, set up the
 initial MessagePipe between two processes, etc.