save steps enhancement

[winglian]

if save_steps is a fraction, calculate the steps based on floor(save_steps * total_steps_per_epoch).

this way if someone were to say 0.5, they could get a checkpoint at half an epoch and the end of an epoch without having to manually figure it out

[NanoCode012]

Taken from discord: _ratio might be interesting as you said.

https://discord.com/channels/1104757954588196865/1111279858136383509/1116366177430667385

[winglian]

this has been resolved with #547