[tepl] intro: explain how the product line is implemented

[Sébastien Wilmet <swilmet src gnome org>]

commit 3c26626f55ef51270e529e7f1a961c9fb72f9217
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Wed Jun 14 10:05:22 2017 +0200

    intro: explain how the product line is implemented

 docs/reference/intro.xml.in |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/docs/reference/intro.xml.in b/docs/reference/intro.xml.in
index 9ded496..c4d6b44 100644
--- a/docs/reference/intro.xml.in
+++ b/docs/reference/intro.xml.in
@@ -44,6 +44,12 @@
   </para>
 
   <para>
+    The library contains a framework part (for now without a plugin system), and
+    other features are available more as a toolkit. Note that the library is far
+    from finished, it is under development.
+  </para>
+
+  <para>
     Maybe some of the Tepl features will be moved to GtkSourceView when it's
     considered more stable. So Tepl can also be seen as an incubator for some
     GtkSourceView features.