Macro frame_benchmarking::validate_pov_mode

macro_rules! validate_pov_mode {
    () => { ... };
    ( $_bench:ident: ; ) => { ... };
    ( $_bench:ident: $_car:path = Ignored ; ) => { ... };
    ( $bench:ident: $_car:path = Ignored $( $storage:path = $_pov_mode:ident )+; ) => { ... };
    ( $bench:ident: $car:path = Measured $( $storage:path = $pov_mode:ident )*; ) => { ... };
    ( $bench:ident: $car:path = MaxEncodedLen $( $storage:path = $pov_mode:ident )*; ) => { ... };
    ( $bench:ident: $key:path = $unknown:ident $( $_storage:path = $_pov_mode:ident )*; ) => { ... };
}

Validates the passed pov_modes.

Checks that:

• a top-level ignored is exclusive
• all modes are valid