[nem-en] errors in reference documentation

[Kamil Dworakowski]

A production taken from reference that has two errors 
(http://nemerle.org/Type_members_%28ref%29#method_parameters):

<method_parameters> ::=
    [ <method_parameters> { ',' <method_parameter> } ]

I think that it should be:

<method_parameters> ::=
    [ <method_parameter> [{ ',' <method_parameter> }] ]

Apart from the extra s on the right side there is also the mistake of 
using {} where [{}] is needed. Am I right?

-- Kamil Dworakowski