Add a `contains(element)` method to the `List` class in the core library, enabling linear search for an element across all list items. Update the `example/set.wren` file to use the new Wren operator syntax for `|`, `+`, `&`, and `-` methods, replacing old function-style parameter definitions with block-style closures. Also fix trailing whitespace throughout the Set example and embed the new `contains` method into the C source string in `src/wren_core.c` for the built-in List class.
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.