patch 8.2.1536: cannot get the class of a character; emoji widths are wrong

Problem:    Cannot get the class of a character; emoji widths are wrong in
            some environments.
Solution:   Add charclass(). Update some emoji widths.  Add script to check
            emoji widths.

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1536,
 /**/
     1535,
 /**/