[gtk+] Document GTK_INSPECTOR_RENDERER

[Matthias Clasen <matthiasc src gnome org>]

commit e70380a4ddc4f4f18f02c0f43d3d22c2f8eaf1ac
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Mar 29 22:48:19 2017 -0400

    Document GTK_INSPECTOR_RENDERER
    
    Also add GTK_INSPECTOR_DISPLAY to the docs at the same time.

 docs/reference/gtk/running.sgml |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)
---
diff --git a/docs/reference/gtk/running.sgml b/docs/reference/gtk/running.sgml
index e8708ce..9f28579 100644
--- a/docs/reference/gtk/running.sgml
+++ b/docs/reference/gtk/running.sgml
@@ -565,12 +565,19 @@ nevertheless.
     <envar>GTK_DEBUG=interactive</envar> environment variable.
   </para>
   <para>
+    There are a few more environment variables that can be set to influence
+    how the inspector renders its UI. <envar>GTK_INSPECTOR_DISPLAY</envar> and
+    <envar>GTK_INSPECTOR_RENDERER</envar> determine the GDK display and
+    the GSK renderer that the inspector is using.
+  </para>
+
+  <para>
     In some situations, it may be inappropriate to give users access to the
     GTK+ inspector. The keyboard shortcuts can be disabled with the
     `enable-inspector-keybinding` key in the `org.gtk.Settings.Debug`
     GSettings schema.
   </para>
- 
+
 </refsect2>
 
 </refsect1>