fix: append() was not returning a type (#84)

append() now returns the underlying array type.
Method lookup was skipped for selector expression on arrays.
Pointer expression was incorrectly parsed as a dereference instead of
type expression.

_test/a20.go

@@ -0,0 +1,19 @@
+package main
+
+import "fmt"
+
+type IntArray []int
+
+func (h *IntArray) Add(x int) {
+	*h = append(*h, x)
+}
+
+func main() {
+	a := IntArray{}
+	a.Add(4)
+
+	fmt.Println(a)
+}
+
+// Output:
+// [4]