patch 8.2.2957: using getchar() in Vim9 script is problematic

Problem:    Using getchar() in Vim9 script is problematic.
Solution:   Add getcharstr(). (closes #8343)
diff --git a/src/version.c b/src/version.c
index b64839e..a1b2c23 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2957,
+/**/
     2956,
 /**/
     2955,