Support new `noreturn` directive

[zaneduffield]

Delphi 13 added a new procedure directive noreturn.

In order to support this we need to add a new impure keyword for it here

pasfmt/core/src/lang.rs

Line 121 in 8be6daf

// Impure keywords

and include it in is_method_directive here

pasfmt/core/src/lang.rs

Line 182 in 8be6daf

pub fn is_method_directive(&self) -> bool {

and add some tests for it here

pasfmt/core/src/defaults/parser/token_consolidation_tests.rs

Line 121 in 8be6daf

method_directive_consolidation_test!(