Deprecated `arg_enum` depends on removed `_clap_count_exprs`

[bgilbert]

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Rust Version

rustc 1.60.0 (Fedora 1.60.0-1.fc35)

Clap Version

3.1.17

Minimal reproducible code

use clap::arg_enum;

arg_enum! {
    pub enum Column {
        A,
        B,
        C,
    }
}

fn main() {}

Steps to reproduce the bug with the above code

cargo build

Actual Behaviour

error[E0433]: failed to resolve: could not find `_clap_count_exprs` in `$crate`
 --> src/main.rs:3:1  |
3 | / arg_enum! {
4 | |     pub enum Column {
5 | |         A,
6 | |         B,
7 | |         C,
8 | |     }
9 | | }
  | |_^ could not find `_clap_count_exprs` in `$crate`
  |
  = note: this error originates in the macro `$crate::arg_enum` (in Nightly builds, run with -Z macro-backtrace for more info)

Expected Behaviour

Code compiles.

Additional Context

c825491 re-added arg_enum, which uses _clap_count_exprs, but in the meantime _clap_count_exprs had been removed by #1970.

Debug Output

Same as above.