Fix image URLs in docs (#1898)

Author: tomlyn

docs/pages/03.03.01-context-menu-handler.md

@@ -74,7 +74,7 @@ Here's an example of a contextMenuHandler:
 
 The above array will produce a context menu like this:
 
-<img src="../assets/context-menu.png" width="300" />
+<img src="../assets/cc-context-menu.png" width="300" />
 
 ### Customizing the default context menu
 
@@ -123,11 +123,11 @@ Dividers can also be added to the context toolbar by specifying 'toolbarItem: tr
 ```
 This will produce a context toolbar like this:
 
-<img src="../assets/context-toolbar.png" width="400" />
+<img src="../assets/cc-context-toolbar.png" width="400" />
 
 And when the overflow icon is clicked, like this:
 
-<img src="../assets/context-toolbar-open-overflow.png" width="400" />
+<img src="../assets/cc-context-toolbar-open-overflow.png" width="400" />
 
 
 #### Warning