Opening the interface xmlNewCharEncodingHandler as requested in #89415

* encoding.c include/libxml/encoding.h: Opening the interface
  xmlNewCharEncodingHandler as requested in #89415
* python/generator.py python/setup.py.in: applied cleanup
  patches from Marc-Andre Lemburg
* tree.c: fixing bug #89332 on a specific case of loosing
  the XML-1.0 namespace on xml:xxx attributes
Daniel
diff --git a/encoding.c b/encoding.c
index d2d5ca2..69b3dac 100644
--- a/encoding.c
+++ b/encoding.c
@@ -1481,9 +1481,10 @@
  * @output:  the xmlCharEncodingOutputFunc to write that encoding
  *
  * Create and registers an xmlCharEncodingHandler.
+ *
  * Returns the xmlCharEncodingHandlerPtr created (or NULL in case of error).
  */
-static xmlCharEncodingHandlerPtr
+xmlCharEncodingHandlerPtr
 xmlNewCharEncodingHandler(const char *name, 
                           xmlCharEncodingInputFunc input,
                           xmlCharEncodingOutputFunc output) {