[polari/docs] Fix link to polari-screenshot.png in introduction.page

[Paul Cutler <pcutler src gnome org>]

commit 88ec8e641c50bc2d1e3388b7b2b74e8331349816
Author: Paul Cutler <paul r cutler gmail com>
Date:   Thu Mar 16 16:02:06 2017 -0500

    Fix link to polari-screenshot.png in introduction.page

 help/C/introduction.page |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/help/C/introduction.page b/help/C/introduction.page
index 40fe617..5ae89ce 100644
--- a/help/C/introduction.page
+++ b/help/C/introduction.page
@@ -31,7 +31,7 @@
     <app>Polari</app> is a simple Internet Relay Chat (IRC) client which integrates with the GNOME desktop 
and enables you to chat with people around the world through large chatrooms or private messaging.
   </p>
 
-  <media type="image" mime="image/png" src="images/polari.png">
+  <media type="image" mime="image/png" src="images/polari-screenshot.png">
        <p>Polari IRC Client</p>
   </media>