patch 7.4.1782

Problem:    strcharpart() does not work properly with some multi-byte
            characters.
Solution:   Use mb_cptr2len() instead of mb_char2len(). (Hirohito Higashi)

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1782,
 /**/
     1781,
 /**/