runtime(doc): Fix notation of "Vim script" and "Vim9 script"

closes: #17213

Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/eval.c b/src/eval.c
index e891164..530cc95 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -2284,7 +2284,7 @@
     {
 	where_T	    where = WHERE_INIT;
 
-	// In a vim9 script, do type check and make sure the variable is
+	// In a Vim9 script, do type check and make sure the variable is
 	// writable.
 	if (check_typval_type(lp->ll_valtype, rettv, where) == FAIL)
 	    return NULL;