patch 8.2.2656: some command line arguments and regexp errors not tested

Problem:    Some command line arguments and regexp errors not tested.
Solution:   Add a few test cases. (Dominique Pellé, closes #8013)
diff --git a/src/version.c b/src/version.c
index 4cf2c0a..c1e795b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2656,
+/**/
     2655,
 /**/
     2654,