stub the type Parser + the function New

(it will automatically make stubs for all the methods on that type)

Co-authored-by: Owen Mansel-Chan <62447351+owen-mc@users.noreply.github.com>

Author: felickz

go/ql/test/query-tests/Security/CWE-643/tst.go

@@ -10,7 +10,7 @@ package main
 //go:generate depstubber -vendor github.com/jbowtie/gokogiri/xml Node
 //go:generate depstubber -vendor github.com/jbowtie/gokogiri/xpath "" Compile
 //go:generate depstubber -vendor github.com/santhosh-tekuri/xpathparser "" Parse,MustParse
-//go:generate depstubber -vendor github.com/lestrrat-go/libxml2/parser "" ParseString
+//go:generate depstubber -vendor github.com/lestrrat-go/libxml2/parser Parser New
 
 import (
 	"net/http"