add the ability to change the pwm frequency for the IS31FL3737B

[Frooastside]

Description

I made the same changes to support changing the PWM frequency with the IS31FL3737B and no longer just the IS31FL3733B.

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[Frooastside]

I don't really know if this is a core change and instead should target the develop branch, but it is definetly not a breaking change.

[zvecr]

if this is a core change and instead should target the develop branch

It would be considered core, and we generally want those to go via develop. It could go directly to master as it should be backwards compatible, though this wouldnt be my preference. I will leave that open to other collabs.

[drashna]

Yeah, I think I would prefer that this go to develop, and through the normal breaking changes cycle.

Mostly, because it's a slippery slope. If it's a small change, and we let it through, how big of a change does it have to be? Etc.

The policy has been that bugfixes are okay to go to master, directly. Eg, stuff that breaks compiling altogether, or breaks behavior.

[Frooastside]

As i said I wasn't sure if it is a core change, now I am. Should I change it to target the develop branch instead?