Add `addAll(other)` method to the List class in both the Wren core library source and its embedded C string representation. The method iterates over the given `other` sequence, appends each element to the list using the existing `add()` method, and returns the original `other` argument to match the documented return behavior. Include a new test file `test/list/add_all.wren` covering basic appending, empty iterable, range input, and return value verification.
The Wren scripts in this directory get converted to C string literals and then inserted into their respective .c files so that the interpreter can load them directly without having to do any file IO.
The script that does this copying is script/generate_builtins.py.
You can invoke using make builtin.