alter user and alter cmd do not have same functions

for alter user,there is a description:

> ALTER USER is now an alias for ALTER ROLE.
>
so,people will think they are the same.but there are differences:

> ALTER USER *name* SET *configuration_parameter* { TO | = } { *value* |
> DEFAULT }

ALTER USER *name* SET *configuration_parameter* FROM CURRENT

ALTER USER *name* RESET *configuration_parameter*

ALTER USER *name* RESET ALL

and

> ALTER ROLE *name* [ IN DATABASE *database_name* ] SET *
> configuration_parameter* { TO | = } { *value* | DEFAULT } ALTER ROLE *name
> * [ IN DATABASE *database_name* ] SET *configuration_parameter* FROM
> CURRENT

ALTER ROLE *name* [ IN DATABASE *database_name* ] RESET *
> configuration_parameter*

ALTER ROLE *name* [ IN DATABASE *database_name* ] RESET ALL

I think we should either metion the differences in doc or make the have no
differences. It took some time to find the later today because I most time
use alter user and think it equel to alter role.