patch 8.2.2973: fix for recovery and diff mode not tested

Problem:    Fix for recovery and diff mode not tested.
Solution:   Add a few more tests. (Yegappan Lakshmanan, closes #8352)
diff --git a/src/version.c b/src/version.c
index af6c11c..25f2d15 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2973,
+/**/
     2972,
 /**/
     2971,