patch 8.2.2388: no easy way to get the maximum or mininum number value

Problem:    No easy way to get the maximum or mininum number value.
Solution:   Add v:numbermax and v:numbermin.
diff --git a/src/version.c b/src/version.c
index c911ed4..6d99990 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2388,
+/**/
     2387,
 /**/
     2386,