Move package xml before copyright

Having the same copyright on all files made the documentation script
to include it multiple times in the package information.

core/encoding/xml/helpers.odin

@@ -1,3 +1,5 @@
+package xml
+
 /*
 	An XML 1.0 / 1.1 parser
 
@@ -6,7 +8,7 @@
 
 	This file contains helper functions.
 */
-package xml
+
 
 // Find parent's nth child with a given ident.
 find_child_by_ident :: proc(doc: ^Document, parent_id: Element_ID, ident: string, nth := 0) -> (res: Element_ID, found: bool) {
@@ -47,4 +49,4 @@ find_attribute_val_by_key :: proc(doc: ^Document, parent_id: Element_ID, key: st
 		if attr.key == key { return attr.val, true }
 	}
 	return "", false
-}
+}