Add missing word from docs.

     *

     * <p class="caution">Note that the system calls this on your

     * service's main thread.  A service's main thread is the same

     * thread where UI operations place for Activities running in the

     * thread where UI operations take place for Activities running in the

     * same process.  You should always avoid stalling the main

     * thread's event loop.  When doing long-running operations,

     * network calls, or heavy disk I/O, you should kick off a new