Add another link to cmap information.
diff --git a/include/freetype.h b/include/freetype.h
index 9f2c453..7c46a77 100644
--- a/include/freetype.h
+++ b/include/freetype.h
@@ -643,7 +643,8 @@ FT_BEGIN_HEADER
/* FT_ENCODING_MS_SYMBOL :: */
/* Corresponds to the Microsoft Symbol encoding, used to encode */
/* mathematical symbols and wingdings. For more information, see */
- /* `http://www.kostis.net/charsets/symbol.htm' and */
+ /* `http://www.microsoft.com/typography/otspec/recom.htm', */
+ /* `http://www.kostis.net/charsets/symbol.htm', and */
/* `http://www.kostis.net/charsets/wingding.htm'. */
/* */
/* This encoding uses character codes from the PUA (Private Unicode */