Computes completion candidates for a partial input line.
Promise-shaped facade over the callback-style completer, for hosts that
answer completion requests asynchronously (a remote surface's tab press).
Completion failures resolve to no candidates; they never reject, matching
the completer's own never-crash contract.
Computes completion candidates for a partial input line.
Promise-shaped facade over the callback-style completer, for hosts that answer completion requests asynchronously (a remote surface's tab press). Completion failures resolve to no candidates; they never reject, matching the completer's own never-crash contract.