patch 8.2.1505: not all file read and writecode is tested

Problem:    Not all file read and writecode is tested.
Solution:   Add a few tests. (Dominique Pellé, closes #6764)
diff --git a/src/version.c b/src/version.c
index 6773a88..843fd43 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1505,
+/**/
     1504,
 /**/
     1503,