* Improve formatting and clarity in "Subset" * Change method name to isSubsetOf Co-authored-by: Eric Leung <eric@erictleung.com> * Change method name to isSubsetOf Co-authored-by: Eric Leung <eric@erictleung.com> * Fix method name in tests * Fix variable name aIsSubsetOfB * Fix method name in solution Co-authored-by: Eric Leung <eric@erictleung.com>