use org.eclipse.core.contenttype.contentTypes extension point

plugins/org.eclipse.dltk.python.core/plugin.xml

diff --git a/plugins/org.eclipse.dltk.python.core/plugin.xml b/plugins/org.eclipse.dltk.python.core/plugin.xml
index 45611f3..47fb621 100644
--- a/plugins/org.eclipse.dltk.python.core/plugin.xml
+++ b/plugins/org.eclipse.dltk.python.core/plugin.xml
@@ -44,7 +44,7 @@
       </parser>
    </extension>
   <extension
-        point="org.eclipse.core.runtime.contentTypes">
+        point="org.eclipse.core.contenttype.contentTypes">
      <content-type
            base-type="org.eclipse.core.runtime.text"
            describer="org.eclipse.dltk.python.core.PythonContentDescriber"