[gnome-builder] help: update basics examples

[Christian Hergert <chergert src gnome org>]

commit 43ed2883a632ffbdc0ecb54e7c98bac16e36889d
Author: Christian Hergert <chergert redhat com>
Date:   Tue Mar 12 15:12:50 2019 -0700

    help: update basics examples

 doc/help/plugins/workbench/basics.rst | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
---
diff --git a/doc/help/plugins/workbench/basics.rst b/doc/help/plugins/workbench/basics.rst
index ba58967c4..87d3cf709 100644
--- a/doc/help/plugins/workbench/basics.rst
+++ b/doc/help/plugins/workbench/basics.rst
@@ -22,6 +22,23 @@ This conveniently allows you to track the state needed for your plugin for each
        def do_unload(self, workbench: Ide.Workbench):
            pass
 
+       def do_workspace_added(self, workspace: Ide.Workspace):
+           pass
+
+       def do_workspace_removed(self, workspace: Ide.Workspace):
+           pass
+
+   class BasicWorkspaceAddin(GObject.Object, Ide.WorkspaceAddin):
+
+       def do_load(self, workspace: Ide.Workspace):
+           pass
+
+       def do_unload(self, workspace: Ide.Workspace):
+           pass
+
+       def do_surface_set(self, surface: Ide.Surface):
+           pass
+
 You will notice that at the top we import the packages we'll be using.
 Here we use the ``GObject`` and ``Ide`` packages from GObject Introspection.
 
@@ -36,4 +53,7 @@ This method is called when the workbench is setup or your plugin is loaded.
 When the ``unload`` virtual method is called the plugin should clean up after itself to leave Builder and 
the workbench in a consistent state.
 This method is called when the workbench is destroyed or your plugin is unloaded.
 
+To simplify tracking workspace surface changes, you can use ``Ide.WorkspaceAddin`` as the second class 
implements.
+This plugin instance will be created for each workspace window.
 
+.. note:: You can limit the types of workspaces that the ``Ide.WorkspaceAddin`` will be instantiated for 
using ``X-Workspace-Kind=primary;editor;greeter;`` in the ``.plugin`` file.