LibWeb: Add FIXME for moving "stop parsing" step for error documents

Corresponds to:
48cd393d1e

Actually doing so was causing crashes and other issues, so I'll leave it
as a FIXME for later.

Libraries/LibWeb/DOM/DocumentLoading.h

@@ -78,11 +78,14 @@ GC::Ref<DOM::Document> create_document_for_inline_content(GC::Ptr<HTML::Navigabl
     // 5. Let document be the result of creating and initializing a Document object given "html", "text/html", and navigationParams.
     auto document = DOM::Document::create_and_initialize(DOM::Document::Type::HTML, "text/html"_string, navigation_params).release_value_but_fixme_should_propagate_errors();
 
-    // 6. Either associate document with a custom rendering that is not rendered using the normal Document rendering rules, or mutate document until it represents the content the
-    //    user agent wants to render.
+    // 6. Either associate document with a custom rendering that is not rendered using the normal Document rendering
+    //    rules, or mutate document until it represents the content the user agent wants to render.
     mutate_document(*document);
 
-    // 7. Return document.
+    // FIXME: 7. Act as if the user agent had stopped parsing document.
+    // We currently do this in the caller instead, to avoid deadlocks.
+
+    // 8. Return document.
     return document;
 }
 

Libraries/LibWeb/HTML/Navigable.cpp

@@ -1407,7 +1407,7 @@ void Navigable::populate_session_history_entry_document(
                     document.set_url(URL::about_error());
                     parser->run();
 
-                    // NOTE: Once the page has been set up, the user agent must act as if it had stopped parsing.
+                    // FIXME: This should go in create_document_for_inline_content() instead.
                     // FIXME: Directly calling parser->the_end results in a deadlock, because it waits for the warning image to load.
                     //        However the response is never processed when parser->the_end is called.
                     //        Queuing a global task is a workaround for now.