patch 8.2.4840: heredoc expression evaluated even when skipping

Problem:    Heredoc expression evaluated even when skipping.
Solution:   Don't evaluate when "skip" is set. (closes #10306)
diff --git a/src/version.c b/src/version.c
index c3b6326..0570614 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4840,
+/**/
     4839,
 /**/
     4838,