Creates a sourcemap view from a file path.

def from_path(filename):
        """Creates a sourcemap view from a file path."""
        filename = to_bytes(filename)
        if NULL_BYTE in filename:
            raise ValueError('null byte in path')
        return ProguardView._from_ptr(rustcall(
            _lib.lsm_proguard_mapping_from_path,
            filename + b'\x00'))