replace references to 'Jetpack Platform' with 'add-on' per review com…

…ment

static-files/md/dev-guide/e10s.md

@@ -19,8 +19,8 @@ parent chrome process.
 The above diagram is a simplified depiction of what happens when a hypothetical
 add-on using the `widget` module is loaded.
 
-First, the Jetpack Platform Loader initializes the Jetpack Platform and loads
-`main.js` in a separate process. We call this the *add-on process*.
+First, the add-on loader initializes the add-on and loads `main.js` in a
+separate process. We call this the *add-on process*.
 
 When `main.js` calls `require("widget")`, the add-on process sends a message to
 the chrome process and awaits a reply.