fix: Fix wrong descend range for add_missing_match_arms

[A4-Tacks]

Example

macro_rules! m { ($expr:expr) => {$expr}} enum Test { A, B, C, } fn foo(t: Test) { m!(match t { Test::A => (), $0}); }

Before this PR

Assist not applicable

After this PR

macro_rules! m { ($expr:expr) => {$expr}} enum Test { A, B, C, } fn foo(t: Test) { m!(match t { Test::A=>(), Test::B => ${1:todo!()}, Test::C => ${2:todo!()},$0 }); }