This reduces ambiguity in how the different "multiple" parts of the API
interact and lowrs the amount of API surface area users have to dig
through to use clap.
For now, this is only a matter of cleaning up the public API. Cleaning
up the implementation is the next step.
Inspired by argcomplete, this provides Rust-implemented completions
- Only bash for now
- No subcommand support
- No flag value support
- No special settings support
- No handling of positions within positionals
- No prioritizing of required or removing of conflicts (including
self-conflicts)