Fix documentation of `num_glyphs'.
diff --git a/include/freetype/freetype.h b/include/freetype/freetype.h
index e2a4e8d..19266df 100644
--- a/include/freetype/freetype.h
+++ b/include/freetype/freetype.h
@@ -790,6 +790,9 @@
/* `num_fixed_sizes'), it is set to the number */
/* of outline glyphs. */
/* */
+ /* For CID-keyed fonts, this value gives the */
+ /* highest CID used in the font. */
+ /* */
/* family_name :: The face's family name. This is an ASCII */
/* string, usually in English, which describes */
/* the typeface's family (like `Times New */