re-enable steepness = 1.00 with 3.30.24

[Rick-Methot-NOAA]

Find that equil_spawn_recr now fails with steepness=1.0 because it tries to create alpha, beta intermediary quantities. Needs warning.

[iantaylor-NOAA]

I think that some of the models used by the IATTC have steepness fixed at 1.0.

@cminte and @HaikunXu, if you have time, could you confirm that changing from SR_BH_steep = 1.0 to SR_BH_steep = 0.999 in one or more of your models produces negligible differences?

[cminte]

@iantaylor-NOAA I can check, I'll wait for the new version @Rick-Methot-NOAA mentioned on the seminar 7/22/2025 and run it.

[Rick-Methot-NOAA]

I will add something to bypass the situation:
if(steepness is fixed and steepness = 1.0) { set R = R0 // ignores steepness}

[Rick-Methot-NOAA]

After looking at the code, I think it is better to redirect users to use recruitment option 4 than to perpetuate misuse of Beverton-Holt. Option 4 omits the steepness parameter entirely and simply sets R^hat = R0 and then applies any time-vary, regime, or dev effects.

[Rick-Methot-NOAA]

Sr_fxn == 4 also omits the bias adjustment.
it does not do anything to reduce the penalty on the recdevs, but probably should. Need to see how WHAM, FIMS, and AMAK are dealing with this.

[Rick-Methot-NOAA]

add code to bypass steepness if h == 1 and not estimated