[gnome-builder] doc: add a blurb on how conditional EditorView addins work

[Christian Hergert <chergert src gnome org>]

commit 96246dd16d5c504466879e373d194d4978914c7c
Author: Christian Hergert <chergert redhat com>
Date:   Wed Jun 28 16:55:05 2017 -0700

    doc: add a blurb on how conditional EditorView addins work

 doc/plugins/editor/index.rst |    1 +
 doc/plugins/editor/view.rst  |   10 ++++++++++
 2 files changed, 11 insertions(+), 0 deletions(-)
---
diff --git a/doc/plugins/editor/index.rst b/doc/plugins/editor/index.rst
index 8da408a..7ee3ae9 100644
--- a/doc/plugins/editor/index.rst
+++ b/doc/plugins/editor/index.rst
@@ -6,6 +6,7 @@ Extending the Editor
    :maxdepth: 1
    :titlesonly:
 
+   view
    buffers
    highlighting
    diagnostics
diff --git a/doc/plugins/editor/view.rst b/doc/plugins/editor/view.rst
new file mode 100644
index 0000000..50c0ec1
--- /dev/null
+++ b/doc/plugins/editor/view.rst
@@ -0,0 +1,10 @@
+#########################
+Extending the Editor View
+#########################
+
+You might want to add additional widgets or perform various operations on the view as the user interacts 
with the code-editor.
+One way to do this is to create an ``Ide.EditorViewAddin`` in your plugin.
+Implementing this interface allows you to be notified whenever a new view is created as well as when the 
current language changes.
+
+Additionally, if you only want your plugin to be enabled when certain languages are active, you can set the 
``X-Editor-View-Languages=c,cplusplus`` keyword in your ``.plugin`` file.
+In the example provided, the plugin interface would be enabled for ``C`` and ``C++`` files.