patch 9.0.0666: spacing-combining characters handled as composing

Problem:    Spacing-combining characters handled as composing, causing text to
            take more space than expected.
Solution:   Handle characters marked with "Mc" not as composing.
            (closes #11282

src/version.c

@@ -699,6 +699,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    666,
 /**/
     665,
 /**/