Block problematic mod-file names

The dynamic file uses as inputs

dynamic(y, x, params, steady_state, it_)

If a user names the mod-file steady_state, there will be an error message

Dot indexing is not supported for variables of this type.

Error in steady_state.dynamic (line 6)
        [residual, g1] = steady_state.dynamic_resid_g1(T, y, x, params, steady_state, it_, true);

See https://forum.dynare.org/t/dynare-error-reporting/17151/3 We should block params and steady_state and ideally also x,y,it_