patch 8.2.2944: Vim9: no error when using job or channel as a string

Problem:    Vim9: no error when using job or channel as a string.
Solution:   Be more strict about conversion to string. (closes #8312)

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2944,
 /**/
     2943,
 /**/