ast, parser, checker: check struct implements non interface type (fix #22200)

[yuyi98]

This PR check struct implements non interface type (fix #22200).

• Check struct implements non interface type.
• Add test.

struct Walker implements Abcde  {
	aaa  string
}

fn main() {}

PS D:\Test\v\tt1> v run .
tt1.v:1:26: error: `Abcde` is not an interface type
    1 | struct Walker implements Abcde  {
      |                          ~~~~~
    2 |     aaa  string
    3 | }

[felipensp]

I've changed the implements_type to be a TypeNode ast node. So the _pos field will not be needed.

See PR #22189

[felipensp]

@yuyi98 You can merge your check to it if you want. 👍🏻

[yuyi98]

Ok, Thanks !

[Delta456]

Good work