EditorHelpBit: Workaround crash renaming named class inheriting `@tool` class

This only addresses the symptom, not the root cause of the problem.

In the MRP of the linked issue, the parent class seems to not be found in DocData
after renaming its child class, which seems weird. Force opening the docs of the
parent class can work it around, so we seem to have inconsistent state.

Changed the same code in EditorHelp for good measure.

Fixes #102718.

editor/editor_help.cpp

@@ -1017,7 +1017,8 @@ void EditorHelp::_update_doc() {
 			class_desc->add_text(nbsp); // Otherwise icon borrows hyperlink from `_add_type()`.
 			_add_type(inherits);
 
-			inherits = doc->class_list[inherits].inherits;
+			const DocData::ClassDoc *base_class_doc = doc->class_list.getptr(inherits);
+			inherits = base_class_doc ? base_class_doc->inherits : String();
 
 			if (!inherits.is_empty()) {
 				class_desc->add_text(" < ");
@@ -3713,7 +3714,8 @@ void EditorHelpBit::_update_labels() {
 
 						_add_type_to_title({ inherits, String(), false });
 
-						inherits = class_list[inherits].inherits;
+						const DocData::ClassDoc *base_class_doc = class_list.getptr(inherits);
+						inherits = base_class_doc ? base_class_doc->inherits : String();
 					}
 
 					title->pop(); // font_size