[libxml2] Fix warnings from apibuild.py

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 5264fa110047c4666457b1efa82c0fa9344ab77f
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Thu Aug 18 20:17:27 2022 +0200

    Fix warnings from apibuild.py

 include/libxml/tree.h       | 2 ++
 include/libxml/xmlexports.h | 2 ++
 2 files changed, 4 insertions(+)
---
diff --git a/include/libxml/tree.h b/include/libxml/tree.h
index 98e20874..4147522c 100644
--- a/include/libxml/tree.h
+++ b/include/libxml/tree.h
@@ -180,8 +180,10 @@ typedef enum {
     /* XML_DOCB_DOCUMENT_NODE= 21 */ /* removed */
 } xmlElementType;
 
+/** DOC_DISABLE */
 /* For backward compatibility */
 #define XML_DOCB_DOCUMENT_NODE 21
+/** DOC_ENABLE */
 
 /**
  * xmlNotation:
diff --git a/include/libxml/xmlexports.h b/include/libxml/xmlexports.h
index aceede5e..e48a08b7 100644
--- a/include/libxml/xmlexports.h
+++ b/include/libxml/xmlexports.h
@@ -67,10 +67,12 @@
  */
 #define XMLPUBVAR XMLPUBLIC extern
 
+/** DOC_DISABLE */
 /* Compatibility */
 #if !defined(LIBXML_DLL_IMPORT)
 #define LIBXML_DLL_IMPORT XMLPUBVAR
 #endif
+/** DOC_ENABLE */
 
 #endif /* __XML_EXPORTS_H__ */