[gnome-builder] help: add blurb about disabling indenters

[Christian Hergert <chergert src gnome org>]

commit fcf5bee60e09bb52cd02114f451ab5bc5a2ff1c1
Author: Christian Hergert <chergert redhat com>
Date:   Sun May 12 23:51:51 2019 -0700

    help: add blurb about disabling indenters
    
    Fixes #913

 doc/help/howto/indentation.rst | 12 ++++++++++++
 1 file changed, 12 insertions(+)
---
diff --git a/doc/help/howto/indentation.rst b/doc/help/howto/indentation.rst
index 74c9b0cdc..99529aead 100644
--- a/doc/help/howto/indentation.rst
+++ b/doc/help/howto/indentation.rst
@@ -33,3 +33,15 @@ On the right you will now see a list of preferences that may be tweaked for that
 Change the indentation level to your desired preference.
 
 .. _editorconfig: http://editorconfig.org/
+
+Disabling an Indenter
+---------------------
+
+If an indenter is being problematic, you can disable it using ``gsettings``.
+The GNU-style C indenter is provided as part of the ``c-pack`` plugin and can be disabled as such:
+
+.. code-block:: sh
+
+   $ flatpak run --command=bash org.gnome.Builder
+   [org.gnome.Builder]$ gsettings set 
"org.gnome.builder.extension-type:/org/gnome/builder/extension-types/c-pack/IdeIndenter/" enabled false
+