Implement tab autocomplete for `ruff config` (#15603)
## Summary
Not the most important feature, but hey... was marked as the good first
issue ;-) fixes #4551
Unfortunately, looks like clap only generates proper completions for
zsh, so this would not make any difference for bash/fish.
## Test Plan
- cargo nextest run
- manual test by sourcing completions and then triggering autocomplete:
```shell
misha@PandaBook ruff % source <(target/debug/ruff generate-shell-completion zsh)
misha@PandaBook ruff % target/debug/ruff config lin
line-length -- The line length to use when enforcing long-lines violations
lint -- Configures how Ruff checks your code.
lint.allowed-confusables -- A list of allowed 'confusable' Unicode characters to ignore
lint.dummy-variable-rgx -- A regular expression used to identify 'dummy' variables, or
lint.exclude -- A list of file patterns to exclude from linting in addition
lint.explicit-preview-rules -- Whether to require exact codes to select preview rules. Whe
lint.extend-fixable -- A list of rule codes or prefixes to consider fixable, in ad
lint.extend-ignore -- A list of rule codes or prefixes to ignore, in addition to
lint.extend-per-file-ignores -- A list of mappings from file pattern to rule codes or prefi
lint.extend-safe-fixes -- A list of rule codes or prefixes for which unsafe fixes sho
lint.extend-select -- A list of rule codes or prefixes to enable, in addition to
lint.extend-unsafe-fixes -- A list of rule codes or prefixes for which safe fixes shoul
lint.external -- A list of rule codes or prefixes that are unsupported by Ru
lint.fixable -- A list of rule codes or prefixes to consider fixable. By de
lint.flake8-annotations -- Print a list of available options
lint.flake8-annotations.allow-star-arg-any -- Whether to suppress `ANN401` for dynamically typed `*args`
...
```
- check command help
```shell
❯ target/debug/ruff config -h
List or describe the available configuration options
Usage: ruff config [OPTIONS] [OPTION]
Arguments:
[OPTION] Config key to show
Options:
--output-format <OUTPUT_FORMAT> Output format [default: text] [possible values: text, json]
-h, --help Print help
Log levels:
-v, --verbose Enable verbose logging
-q, --quiet Print diagnostics, but nothing else
-s, --silent Disable all logging (but still exit with status code "1" upon detecting diagnostics)
Global options:
--config <CONFIG_OPTION> Either a path to a TOML configuration file (`pyproject.toml` or `ruff.toml`), or a TOML `<KEY> =
<VALUE>` pair (such as you might find in a `ruff.toml` configuration file) overriding a specific
configuration option. Overrides of individual settings using this option always take precedence over
all configuration files, including configuration files that were also specified using `--config`
--isolated Ignore all configuration files
```
- running original command
```shell
❯ target/debug/ruff config
cache-dir
extend
output-format
fix
unsafe-fixes
fix-only
show-fixes
required-version
preview
exclude
extend-exclude
extend-include
force-exclude
include
respect-gitignore
builtins
namespace-packages
target-version
src
line-length
indent-width
lint
format
analyze
```
