C++ completion ?

MetaKernel has a get_completions callback that should return an array of keywords.

• https://metakernel.readthedocs.io/en/latest/source/api.html#metakernel.MetaKernel.get_completions
• example here for python: https://github.com/Calysto/metakernel/blob/2de5d373c41d7b4af3879c2764fdbe904cc12378/metakernel/magics/python_magic.py#L137

Maybe we can use LSP (Language Server Protocol) and call clangd or ccls