Fix comment for option periodic_compaction_seconds (#11227)

Summary:
the comment for option `periodic_compaction_seconds` only mentions support for Leveled and FIFO compaction, while the implementation supports all compaction styles after #5970. This PR updates comment to reflect this.

Pull Request resolved: #11227

Reviewed By: ajkr

Differential Revision: D43325046

Pulled By: cbi42

fbshipit-source-id: 2364dcb5a01cd098ad52c818fe10d621445e2188

include/rocksdb/advanced_options.h

@@ -863,7 +863,9 @@ struct AdvancedColumnFamilyOptions {
   // age is based on the file's last modified time (given by the underlying
   // Env).
   //
-  // Supported in Level and FIFO compaction.
+  // Supported in all compaction styles.
+  // In Universal compaction, rocksdb will try to do a full compaction when
+  // possible, see more in UniversalCompactionBuilder::PickPeriodicCompaction().
   // In FIFO compaction, this option has the same meaning as TTL and whichever
   // stricter will be used.
   // Pre-req: max_open_file == -1.