Add missing k-diffusion sigma params to infotext

[catboxanon]

Description

Put these in the infotext now that they actually all work. :^)

Related:
#12354
#12356
#12357

Checklist:

• I have read contributing wiki page
• I have performed a self-review of my own code
• My code follows the style guidelines
• My code passes tests

[AUTOMATIC1111]

Accessing p.override_settings does not seem right. The values would be in shared.opts.

[catboxanon]

See the related PRs and the comment in this commit for why I'm doing it like this. They're currently defined in StableDiffusionProcessing and they're initially read from opts there.

[AUTOMATIC1111]

what I mean is,

p.override_settings.get('s_churn', p.s_churn)

should be

getattr(opts, 's_churn', p.s_churn)

[catboxanon]

Fixed now. Linter is complaining about d86d12e, not actually anything from this PR