`none-ls` deprecated a lot of unmaintained builtins, or ones that they
find has been replaced by a compete LSP server.
This removes those deprecated builtins, or uses a shim until I migrate
to the relevant LSP configuration (for `bash-language-server`).
The plug-in now configures itself automatically.
I could also set `vim.g.skip_ts_context_commentstring_module = true`,
but that should be removed soon enough anyway, and I would forget to
remove it...
Bruno BELANYI