Add a note on AppRequest for source download

doc/debugger.rst

@@ -1866,6 +1866,8 @@ AppRequest is used to make requests to the target which are not directly
 related to Ecmascript execution and may be implementation-dependent.  For
 example, an AppRequest might be used to:
 
+* Download source files directly from the debug target file system
+
 * Change the frame rate of a game engine
 
 * Reset/reboot an embedded target device while debugging

website/guide/debugger.html

@@ -82,8 +82,9 @@ missing.  Debug clients and debug targets may also implement application
 specific commands (AppRequest) and notifications (AppNotify) for richer
 integration which can be used when both the client and the target support
 them (they're easy and safe to ignore if not supported).  Custom commands
-and notifications allow e.g. deep inspection of the state of a custom target
-specific memory allocator, rebooting the target on command, etc.</p>
+and notifications allow e.g. downloading of source files directly from the
+target, deep inspection of the state of a custom memory allocator, rebooting
+the target on command, etc.</p>
 
 <p>For more details on the implementation and how to get started, see:</p>
 <ul>