[clap_mangen]fix: use proper sub-command name in manpages

Generate subcommand alias

This continues the work started with the fix for #4273. There was
another bug caused by using th...

With the previous fixes for #4273 and #4280 in place, it's now easy to
add support for subcomman...

Only zsh includes completion for visible aliases of subcommands. Let's
show that in tests.

There seems to be little reason to return early with an empty list
when there are no subcommands...

Early in the Bash-completion script, we build up a string that
identifies the command or subcomm...

The `text` variable here is clearly never empty, so don't check if it
is.

I want to add support for completion of arguments for aliased
subcommands so it's nice to have a...

It's useful when testing to have a subcommand in the examples.

The derive-based example has a `///` comment on one argument, which
ends up as a description for...

The example binaries were renamed in 89c2b3bb0d88, but the commands in
them were not, making the...

fix(error): Specialize the self-conflicts error

Inspired by rust-lang/cargo#11159

fix(error): Polish up errors a little

fix(parser): Allow one-off self-overrides

bat needed this.

See also #4261

fix(complete): Fix zsh handling of multiple arguments

docs(complete): Ensure examples work

fix(derive): Ensure clap/structopt attributes still work

Fix inline code snippet typos

Fixes #4272

The problem with updating all code to use non-deprecated APIs, there
aren't tests for the old wa...

There are a couple of typos where a backtick is missing / too much which results in slightly bro...

fix(mangen): Respect more hide values

fix(error): Polish `--flag=bad-value` error

docs: Update multiline usage override rules

When we restuctured the examples, we lost the notes on how they should
be structured, so this ad...

The styling of usage has changed in #4188 such that the usage string is on
the same line as the ...

fix(parser): Conflict-with-self is back on by default

See #4261 for more details

perf: Drop use of Into::into for '?'

For binary size, this only dropped 0.2 KiB

For performance, before:
- parse_rustup_with_sc t...

fix(help)!: Wrapping is behind wrap_help

If users don't want `wrap_help` feature, they can put newlines in where
needed. Seems odd to su...

feat(parser): Support more types with `value_parser!`

Last time I tried this, I wasn't able to resolve the lifetime issues. I
seemed to have gotten i...

feat: Allow users to render usage, help, and errors with ANSI

This gives users the control over where clap outputs while still getting
colors. For users who ...

This will open us up to providing the user with access to the styled
version in the future.

The writer is less convenient and isn't offering any performance
benefits of avoidign the extra ...

doc(changelog): error-context, help and usage feature flags

docs: Clarify value parser

Things that tripped up a user
- Derive reference was misunderstood to say that the only alternat...

This was missed in the migration to the reference being on docs.rs. Not
feeling its worth findi...

docs: a comma felt wrong there

fix(error): Use a non-generic Error alias

The likelihood of using this is a lot lower now with `KindFormatter` and
`error-context` feature...