builtin help function

[shoebill]

function: function name { COMMANDS ; } or name () { COMMANDS ; }
    Define shell function.

    Create a shell function named NAME.  When invoked as a simple command,
    NAME runs COMMANDs in the calling shell's context.  When NAME is invoked,
    the arguments are passed to the function as $1...$n, and the function's
    name is in $FUNCNAME.

    Exit Status:
    Returns success unless NAME is readonly.