Previously we only hide company-mode's in-line preview when there was
only a single result. This meant that it didn't show the one result
anywhere.
This allows company-mode to still show it's regular popup even when
there's only one result.
I opted for accepting copilot completions using C-<tab> /
<backtab> (shift+tab) instead of regular tab, as it was often getting in
the way of yasnippet and lsp completion suggestions. This allows a more
explicit acceptance of Copilot suggestions.
