patch 8.2.4823: concat more than 2 strings in :def function is inefficient

Problem:    Concatenating more than 2 strings in a :def function is
            inefficient.
Solution:   Add a count to the CONCAT instruction. (closes #10276)
diff --git a/src/version.c b/src/version.c
index 612d9e0..b060d5e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4823,
+/**/
     4822,
 /**/
     4821,