Update levels target size option comments.

kvrocks.conf

@@ -598,7 +598,7 @@ rocksdb.enable_blob_garbage_collection yes
 rocksdb.blob_garbage_collection_age_cutoff 25
 
 
-# The purpose of this option is to dynamically adjust the upper limit of
+# The purpose of following three options are to dynamically adjust the upper limit of
 # the data that each layer can store according to the size of the different 
 # layers of the LSM. Enabling this option will bring some improvements in
 # deletion efficiency and space amplification, but it will lose a certain