Indent mode Attributes declaration compatibility with default mode

[Cynede]

e.g.

for now with indent mode you must

[foo]\
bar

I want:

[foo]
bar

[Cynede]

it's failing here in MainParser.n but I really feel that I can't parse the parser's code well

line 3316

              }

            | _ => fatal_error(tok, "expecting expression"); NO
          };