[yuyi98]

This PR fix enum field with const value (fix #21916).

• Fix enum field with const value.
• Add test.

enum Foo {
	a = c
	b = 1
	c = 2
}

const c = 0

fn main() {
	mut foo := Foo.c
	foo = .a
	ret := match foo {
		.a { 'a' }
		.b { 'b' }
		.c { 'c' }
	}
	println(ret)
	assert ret == 'a'
}

PS D:\Test\v\tt1> v run .    
a

[spytheman]

Excellent work.