patch 8.2.4866: duplicate code in "get" functions

Problem:    Duplicate code in "get" functions.
Solution:   Use get_var_from() for getwinvar(), gettabvar(), gettabwinvar()
            and getbufvar(). (closes #10335)
diff --git a/src/version.c b/src/version.c
index bf2c8dc..17bcfd1 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4866,
+/**/
     4865,
 /**/
     4864,