fix(derive): Provide derive-friendly deprecation messages

[epage]

This is a step towards #3822. I'd say this fixes it but I'd want some
user acceptance before doing so.

To do this, we

• Mask all ArgMatches deprecation messages with assumption being that any message from these has its roots in an augment_args deprecation. You can see the raw deprecations with clap_derive/raw-deprecation
• Create call generated functions with a targeted deprecation message that we call for each parse case.
• Mask all deprecation messages for implicit Arg methods, delegating to the messages for the generated functions

We intentionally do not provide a deprecation message for implicit parse attributes since resolving that is just busywork that most likely won't help users in migrating to clap 4.

I had originally assumed this would be difficult to be precise in our allow and deprecations but I found place to split up the calls. Its not completely precise but it should be good enough in the short term.

Example messages

warning: use of deprecated function `<legacy::custom_string_parsers::DefaultedOpt as clap::Args>::augment_args::parse_from_str`: Replaced with `#[clap(value_parser = ...)]`
   --> tests/derive/legacy/custom_string_parsers.rs:167:25
    |
167 |     #[clap(short, parse(from_str))]
    |                         ^^^^^^^^

warning: use of deprecated function `<legacy::custom_string_parsers::DefaultedOpt as clap::Args>::augment_args_for_update::parse_try_from_str`: Replaced with `#[clap(value_parser = ...)]`
   --> tests/derive/legacy/custom_string_parsers.rs:170:25
    |
170 |     #[clap(short, parse(try_from_str))]
    |                         ^^^^^^^^^^^^


warning: use of deprecated function `<legacy::custom_string_parsers::PathOpt as clap::Args>::augment_args::parse_from_os_str`: Replaced with `#[clap(value_parser)]` for `PathBuf` or `#[clap(value_parser = ...)]` with a custom `TypedValueParser`
  --> tests/derive/legacy/custom_string_parsers.rs:23:31
   |
23 |     #[clap(short, long, parse(from_os_str))]
   |                               ^^^^^^^^^^^
   |
   = note: `#[warn(deprecated)]` on by default

warning: use of deprecated function `<legacy::custom_string_parsers::PathOpt as clap::Args>::augment_args::parse_from_os_str`: Replaced with `#[clap(value_parser)]` for `PathBuf` or `#[clap(value_parser = ...)]` with a custom `TypedValueParser`
  --> tests/derive/legacy/custom_string_parsers.rs:23:31
   |
23 |     #[clap(short, long, parse(from_os_str))]
   |                               ^^^^^^^^^^^
   |
   = note: `#[warn(deprecated)]` on by default

warning: use of deprecated function `<legacy::custom_string_parsers::Occurrences as clap::Args>::augment_args::parse_from_occurrences`: Replaced with `#[clap(action = ArgAction::Count)]` with a field type of `u8`
   --> tests/derive/legacy/custom_string_parsers.rs:207:31
    |
207 |     #[clap(short, long, parse(from_occurrences))]
    |                               ^^^^^^^^^^^^^^^^

warning: use of deprecated function `<legacy::custom_string_parsers::Occurrences as clap::Args>::augment_args::parse_from_occurrences`: Replaced with `#[clap(action = ArgAction::Count)]` with a field type of `u8`
   --> tests/derive/legacy/custom_string_parsers.rs:219:50
    |
219 |     #[clap(short, long, parse(from_occurrences = foo))]
    |                                                  ^^^

warning: use of deprecated function `<legacy::flags::non_bool_type_flag::Opt as clap::Args>::augment_args_for_update::parse_from_flag`: Replaced with `#[clap(action = ArgAction::SetTrue)]`
  --> tests/derive/legacy/flags.rs:85:47
   |
85 |         #[clap(short, long, parse(from_flag = parse_from_flag))]
   |                                               ^^^^^^^^^^^^^^^

• We encourage busywork for users accepting a PathBuf and correctly set the parse(from_os_str). Correctly detecting this to not show it would add another level of work and we'd need to have some way to tell users when they upgrade to clap 4 what the correct replacement for parse(from_os_str) is (nothing).
• We're not providing much guidance when users that only specify parse(from_str),. etc