DMN12 — FEEL precedence for function definition

on page 109: "Operator precedence is given by the order of the alternatives in grammar rules 1, 2 and 4, in order from lowest to highest."

But grammar rule 2.a and 1.b contains "function definition". Therefore the precedence of a function definition is not clearly specified. Should we use 2.a (lower precedence) or 1.b (higher precedence) for a function definition?

remove redundant grammar rule for function defn and reverse rules 1a and 1b

The current grammar has a duplicate reference to the function definition rule. Rules 1a and 1b are also in the wrong priority order.