commit 5bc7e4ee2cad7f715db34fc33cadd1e28fd74b1b
Author: Alexander Korotkov <a.korotkov@postgrespro.ru>
Date:   Mon May 7 19:03:05 2018 +0300

    Tab-complete support for vacuum_cleanup_index_scale_factor reloption
    
    857f9c36 has introduced vacuum_cleanup_index_scale_factor reloption, but
    psql tab-complete support for it was missing.  So, add it.

diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index b431efc983..7bb47eadc6 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1855,13 +1855,15 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_CONST("(");
 	/* ALTER INDEX <foo> SET|RESET ( */
 	else if (Matches5("ALTER", "INDEX", MatchAny, "RESET", "("))
-		COMPLETE_WITH_LIST7("fillfactor", "recheck_on_update",
+		COMPLETE_WITH_LIST8("fillfactor", "recheck_on_update",
+							"vacuum_cleanup_index_scale_factor", /* BTREE */
 							"fastupdate", "gin_pending_list_limit", /* GIN */
 							"buffering",	/* GiST */
 							"pages_per_range", "autosummarize"	/* BRIN */
 			);
 	else if (Matches5("ALTER", "INDEX", MatchAny, "SET", "("))
-		COMPLETE_WITH_LIST7("fillfactor =", "recheck_on_update =",
+		COMPLETE_WITH_LIST8("fillfactor =", "recheck_on_update =",
+							"vacuum_cleanup_index_scale_factor =", /* BTREE */
 							"fastupdate =", "gin_pending_list_limit =", /* GIN */
 							"buffering =",	/* GiST */
 							"pages_per_range =", "autosummarize ="	/* BRIN */