patch 8.2.4731: the changelist index is not remembered per buffer

Problem:    The changelist index is not remembered per buffer.
Solution:   Keep the changelist index per window and buffer. (closes #10135,
            closes #2173)
diff --git a/src/version.c b/src/version.c
index fdb2e46..57e1fed 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4731,
+/**/
     4730,
 /**/
     4729,