patch 8.2.2825: code in checkreadonly() not fully tested

Problem:    Code in checkreadonly() not fully tested.
Solution:   Add more tests. (Dominique Pellé, closes #8169)
diff --git a/src/version.c b/src/version.c
index 435117d..a72cd3c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2825,
+/**/
     2824,
 /**/
     2823,