node: manually implement Debug I got too irritated today with the default Debug implementation of hg::revlog::Node while playing with a new parser. This isn't quite what I wanted, but it wasn't much code and it at least gives you output that's easy to visually compare to a node.hex()ed identifier from the Python side of things. Sadly, this doesn't influence the output in lldb or the VSCode debugger extension that uses lldb under the covers, but it at least means debug prints are a little more useful. Differential Revision: https://phab.mercurial-scm.org/D12608