patch 8.2.3304: popup window title with wide characters is truncated

Problem:    Popup window title with wide characters is truncated.
Solution:   Use vim_strsize() instead of MB_CHARLEN(). (Naruhiko Nishino,
            closes #8721)

src/version.c

@@ -755,6 +755,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3304,
 /**/
     3303,
 /**/