patch 8.2.0512: Vim9: no optional arguments in func type

Problem:    Vim9: no optional arguments in func type.
Solution:   Check for question mark after type.  Find function reference
            without function().

src/version.c

@@ -738,6 +738,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    512,
 /**/
     511,
 /**/