[gtk+] Revert "Update the migration guide"

[Matthias Clasen <matthiasc src gnome org>]

commit a1e03346d9d22e49835578b339e266dc19a69772
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Nov 7 15:05:28 2016 -0500

    Revert "Update the migration guide"
    
    This reverts commit b86816438147ffe61959218524f59c44581ee006.

 docs/reference/gtk/migrating-3to4.xml |   18 +-----------------
 1 files changed, 1 insertions(+), 17 deletions(-)
---
diff --git a/docs/reference/gtk/migrating-3to4.xml b/docs/reference/gtk/migrating-3to4.xml
index c9d946e..e8ce306 100644
--- a/docs/reference/gtk/migrating-3to4.xml
+++ b/docs/reference/gtk/migrating-3to4.xml
@@ -133,7 +133,7 @@
     <section>
       <title>Adapt to GtkWidget's size request changes</title>
       <para>
-        GTK+ 3 used five different virtual functions in GtkWidget to
+        GTK+3 used five different virtual functions in GtkWidget to
         implement size requisition, namely the gtk_widget_get_preferred_width()
         family of functions. To simplify widget implementations, GTK+4 uses
         only one virtual function, GtkWidgetClass::measure() that widgets
@@ -141,22 +141,6 @@
       </para>
     </section>
 
-    <section>
-      <title>Don't use symbolic colors in your CSS</title>
-      <para>
-        GTK+ 4 does not support @define-color and symbolic colors anymore.
-        We recommend that you use a css preprocessor like sass instead.
-      </para>
-    </section>
-
-    <section>
-      <title>Don't use -gtk-gradient in your CSS</title>
-      <para>
-        GTK+ now supports standard CSS syntax for both linear and radial
-        gradients, just use those.
-      </para>
-    </section>
-
   </section>
 
 </chapter>