x.encoding.asn1: cleanup code and comments (#22847)

vlib/x/encoding/asn1/any.v

@@ -5,29 +5,23 @@ module asn1
 
 // ANY DEFINED BY
 //
-@[noinit]
-pub struct Any {
-mut:
-	marker string = 'any'
+pub struct AnyDefinedBy {
 pub:
-	params Element
+	// default to null element
+	params Element = Null{}
 }
 
-// Any.new creates a new ANY DEFINED BY element with marker as an identifier.
-pub fn Any.new(marker string, params Element) Any {
-	return Any{marker, params}
+// AnyDefinedBy.new creates a new ANY DEFINED BY element.
+pub fn AnyDefinedBy.new(params Element) AnyDefinedBy {
+	return AnyDefinedBy{params}
 }
 
 // tag returns the underlying tag of ANY DEFINED BY element.
-pub fn (a Any) tag() Tag {
+pub fn (a AnyDefinedBy) tag() Tag {
 	return a.params.tag()
 }
 
 // payload returns the underlying payload of ANY DEFINED BY element.
-pub fn (a Any) payload() ![]u8 {
+pub fn (a AnyDefinedBy) payload() ![]u8 {
 	return a.params.payload()!
 }
-
-fn (a Any) params() Element {
-	return a.params
-}