[...]
       help [-dms] [pattern]
              Display  helpful information about builtin commands.  If pattern is specified, help
              gives detailed help on all commands matching pattern; otherwise help  for  all  the
              builtins and shell control structures is printed.
              -d     Display a short description of each pattern
              -m     Display the description of each pattern in a manpage-like format
              -s     Display only a short usage synopsis for each pattern

              The return status is 0 unless no command matches pattern.
[...]

help: help [-dms] [minta ...]
    Display information about builtin commands.
    
    Displays brief summaries of builtin commands.  If PATTERN is
    specified, gives detailed help on all commands matching PATTERN,
    otherwise the list of help topics is printed.
    
    Options:
      -d        output short description for each topic
      -m        display usage in pseudo-manpage format
      -s        output only a short usage synopsis for each topic matching
                PATTERN
    
    Arguments:
      PATTERN   Pattern specifying a help topic
    
    Exit Status:
    Returns success unless PATTERN is not found or an invalid option is given.