Make `--doctool` create directories if they don't exist

This prevents errors due to missing directories when generating
engine documentation.

This closes #17297.

main/main.cpp

@@ -1374,7 +1374,7 @@ bool Main::start() {
 		{
 			DirAccessRef da = DirAccess::open(doc_tool);
 			if (!da) {
-				ERR_EXPLAIN("Argument supplied to --doctool must be a base godot build directory");
+				ERR_EXPLAIN("Argument supplied to --doctool must be a base Godot build directory");
 				ERR_FAIL_V(false);
 			}
 		}
@@ -1392,12 +1392,23 @@ bool Main::start() {
 			doc_data_classes[name] = path;
 			if (!checked_paths.has(path)) {
 				checked_paths.insert(path);
+
+				// Create the module documentation directory if it doesn't exist
+				DirAccess *da = DirAccess::create_for_path(path);
+				da->make_dir_recursive(path);
+				memdelete(da);
+
 				docsrc.load_classes(path);
 				print_line("Loading docs from: " + path);
 			}
 		}
 
 		String index_path = doc_tool.plus_file("doc/classes");
+		// Create the main documentation directory if it doesn't exist
+		DirAccess *da = DirAccess::create_for_path(index_path);
+		da->make_dir_recursive(index_path);
+		memdelete(da);
+
 		docsrc.load_classes(index_path);
 		checked_paths.insert(index_path);
 		print_line("Loading docs from: " + index_path);