Fix bug in unquoted_node_name to support multiple node blocks

Thanks to an oversight, when the `unquoted_node_name` check was building a list of name tokens, it would determine the end of the list by finding the first `{` token in the file, rather than the first `{` that comes after that `node` token. This would prevent it from checking the names for any subsequent `node` blocks in the file.

Closes #343