Add a comment about valid encoding types for ID3v2 tags.

CCBUG:135122


git-svn-id: svn://anonsvn.kde.org/home/kde/trunk/kdesupport/taglib@649003 283d02a7-25f6-0310-bc7c-ecb5cbfe19da

taglib/mpeg/id3v2/id3v2framefactory.h

@@ -88,6 +88,8 @@ namespace TagLib {
        * \a encoding.  If no value is set the frames with either default to the
        * encoding type that was parsed and new frames default to Latin1.
        *
+       * Valid string types for ID3v2 tags are Latin1, UTF8, UTF16 and UTF16BE.
+       *
        * \see defaultTextEncoding()
        */
       void setDefaultTextEncoding(String::Type encoding);