The error message emitted when a left brace is expected after a class body
incorrectly referenced a closing brace '}' instead of the required opening
brace '{'. This fix updates the error string in the `classDefinition` function
within `src/wren_compiler.c` to accurately describe the expected token.
- Update two `io.write` calls to `IO.print` in doc examples for consistency
- Fix parameter name from `bar` to `arg` in two example method call resolutions