Documentation typo.
diff --git a/include/freetype/ftlcdfil.h b/include/freetype/ftlcdfil.h
index 4cd999a..9e3b425 100644
--- a/include/freetype/ftlcdfil.h
+++ b/include/freetype/ftlcdfil.h
@@ -88,7 +88,7 @@ FT_BEGIN_HEADER
* [0x10, 0x50, 0x60, 0x50, 0x10] ,
* }
*
- * where `a' has value 0x30 and `b' value 0x20. The weights in filter
+ * where `a' has value 0x30 and `c' value 0x20. The weights in filter
* may have a sum larger than 0x100, which increases coloration slightly
* but also improves contrast.
*/