This also has the side effect of always using the "smart usage" which is
why the tests changed.

fix(help): Ensure consistency in usage

fix(help): Consistently use `[]` for positionals

refactor(help): Prep for usage fixes

In the usaeg we use `[]` but in the arg list we use `<>`.

fix: Deprecate _os variants

PR #4096 made them redundant

fix(help): Command::print_help should respect disable_colored_help

GitHub Workflows security hardening

fix(help): Do not propagate global args to help

This prevents global args from showing in help completions,
since help completions should only s...

fix(derive): Remove structopt attribute support

refactor(derive): Prepare for builder attributes

feat(complete): Add completion for help subcommands

* Copy hide flag

* Revert global args special handling. Another commit will
address the issue o...

fix(derive): Remove error case for default_value

fix(derive): Remove deprecated arg_enum attribute

fix(help): Don't dim placeholders

This came from feedback: https://rust-lang.zulipchat.com/#narrow/stream/220302-wg-cli/topic/Help...

fix(help): Shift focus to subcommands, when present

In surveying various tools and CLI parsers, I noticed they list the
subcommands first. This put...

fix(help): Don't rely on ALL CAPS for headers

I see them fulfilling two roles
- A form of bolding
- As a callback to their placeholder in usag...

fix(error): Don't underline indentation

Fix abort message when deriving non-unit enum variants

Clarify that only unit variants are fully supported, and that
non-unit variants must be skipped.

fix(help): Use a more neutral palette

feat: Allow stylized usage

Fixes #2963

* Manual subtree copy to ensure correct behavior and settings
* Always set ExpandHelpSubcommandT...

Adds parser flags to toggle whether to run the
expensive clone logic for completions case.

Help...

feat(help): Open the door for user styling in the future

This ended up favoring the help implementation

While this doesn't reduce size, it cleans things up to make it easier

This adds about 5 KiB to `.text`

This dropped us about 1.8 KiB

The immediate benefit is binary size but this also makes us more
flexible on the implementation,...

docs: overriding multi-line usage

This added about 4 KiB to `.text` which makes sense since we duplicated
logic.

This added about 10 KiB to the `.text` which I cannot explain why

perf(error): Allow custmizing formatting

For now, there isn't much a custom implementation can do.

Going from `Rich` to `Null` drops abo...

Looks like this dropped 2 KiB

refactor(help): Prepare for user-visible styled string

This is prep for creating a formatter trait to select alternative
implementations for errors.

fix: Show possible values in generated man file

Noticed that possible values would not show up for Positional arguments
as well. Decided to add ...

This makes sure we take into account the setting that possible args
is hidden

This adds feature parity for mangen with the standard help output. Users
will now see the list o...

This is prep for making it public

The performance gains of writing directly to the writer are not worth
the complexity. Output is...

fix: Don't pollute root with str types

Extend Command::override_usage() doc string to describe how to format
multiple usage lines to be...

fix: Switch to owned types

The binary size and performance difference is enough to make it
configurable.

Code size:
- defa...

Impact
- Binary size: 556.6 KiB to 578.4 KiB to 574.6 KiB
- build time: 9.4581 us
- parse time: ...