LibJS: Add ECMA-262 section/title/URL comments almost everywhere

As mentioned on Discord earlier, we'll add these to all new functions
going forward - this is the backfill. Reasons:

- It makes you look at the spec, implementing based on MDN or V8
  behavior is a no-go
- It makes finding the various functions that are non-compliant easier,
  in the future everything should either have such a comment or, if it's
  not from the spec at all, a comment explaining why that is the case
- It makes it easier to check whether a certain abstract operation is
  implemented in LibJS, not all of them use the same name as the spec.
  E.g. RejectPromise() is Promise::reject()
- It makes it easier to reason about vm.arguments(), e.g. when the
  function has a rest parameter
- It makes it easier to see whether a certain function is from a
  proposal or Annex B

Also:

- Add arguments to all functions and abstract operations that already
  had a comment
- Fix some outdated section numbers
- Replace some ecma-international.org URLs with tc39.es

Userland/Libraries/LibJS/Runtime/IteratorOperations.cpp

@@ -10,6 +10,7 @@
 
 namespace JS {
 
+// 7.4.1 GetIterator ( obj [ , hint [ , method ] ] ), https://tc39.es/ecma262/#sec-getiterator
 Object* get_iterator(GlobalObject& global_object, Value value, IteratorHint hint, Value method)
 {
     auto& vm = global_object.vm();
@@ -37,6 +38,7 @@ Object* get_iterator(GlobalObject& global_object, Value value, IteratorHint hint
     return &iterator.as_object();
 }
 
+// 7.4.2 IteratorNext ( iteratorRecord [ , value ] ), https://tc39.es/ecma262/#sec-iteratornext
 Object* iterator_next(Object& iterator, Value value)
 {
     auto& vm = iterator.vm();
@@ -66,11 +68,13 @@ Object* iterator_next(Object& iterator, Value value)
     return &result.as_object();
 }
 
+// 7.4.6 IteratorClose ( iteratorRecord, completion ), https://tc39.es/ecma262/#sec-iteratorclose
 void iterator_close([[maybe_unused]] Object& iterator)
 {
     TODO();
 }
 
+// 7.4.10 IterableToList ( items [ , method ] ), https://tc39.es/ecma262/#sec-iterabletolist
 MarkedValueList iterable_to_list(GlobalObject& global_object, Value iterable, Value method)
 {
     auto& vm = global_object.vm();
@@ -86,6 +90,7 @@ MarkedValueList iterable_to_list(GlobalObject& global_object, Value iterable, Va
     return values;
 }
 
+// 7.4.8 CreateIterResultObject ( value, done ), https://tc39.es/ecma262/#sec-createiterresultobject
 Value create_iterator_result_object(GlobalObject& global_object, Value value, bool done)
 {
     auto& vm = global_object.vm();