Regression test for 'references' bug golang/go#60622:
references to methods of generics were missing.

-- go.mod --
module example.com
go 1.18

-- a/a.go --
package a

type G[T any] struct{}

func (G[T]) M() {} //@loc(Mdef, "M"), refs(Mdef, Mdef, Mref)

-- b/b.go --
package b

import "example.com/a"

func _() {
	new(a.G[int]).M() //@loc(Mref, "M")
}
