fmt: fix import selective with interface implements (fix #22200)

[yuyi98]

This PR fix import selective with interface implements (fix #22200).

• Fix import selective with interface implements.
• Add test.

vlib\v\fmt\tests\import_selective_with_implements_keep.vv

import v.ast.walker { Visitor }
import v.ast { Node }

struct Walker implements Visitor {
	aaa string
}

fn (mut n Walker) visit(node &Node) ! {
	panic('not implemented')
}

[spytheman]

Good work.