Allocation-free debouncing

[NilsIrl]

Allocate memory for debouncing algorithms statically.

Description

Some keyboards do not support memory allocation and this commit makes it possible to use debouncing algorithms that previously required allocation on those keyboards.

The num_rows variable was added to debounce_init and debounce to support split keyboards but the value passed to those functions is always ROWS_PER_HAND so it is safe to use the ROWS_PER_HAND macro instead similarly to how MATRIX_COLS is assumed to be correct.

Beyond changes to quantum, some of the keyboards had to be updated to support the change of signature, and documentation for custom matrix was also updated.

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).

[fauxpark]

ROWS_PER_HAND is defined in the following matrix.c files, but has the same value so does not emit an error:

halfcliff
keychron/q10
keychron/q12
keychron/q1v2
keychron/q3
keychron/q5
keychron/q6
keychron/q65
keychron/v1 (errors because it's actually `MATRIX_ROWS` instead of `(MATRIX_ROWS)`)
keychron/v10
keychron/v3
keychron/v5
keychron/v6
nullbitsco/snap
sekigon/grs_70ec
whale/sk/v3

These boards may be an issue because they have ROWS_PER_HAND defined as (MATRIX_ROWS / 2) but are not marked as split keyboards:

handwired/dygma/raise
keyboardio/model01
moonlander

[NilsIrl]

I've removed the definition of ROWS_PER_HAND in all the keyboards but the three mentioned.

For the 3 keyboards which define ROWS_PER_HAND as (MATRIX_ROWS / 2) but are not marked as split keyboard, looking at physical pictures of these keyboards, they are split keyboards so I would be tempted to set SPLIT_KEYBOARD for them but I'd be worried of side effects as ROWS_PER_HAND is used multiple times in quantum/.

Pinging the maintainers/author of the respective keyboard firmwares, maybe they are able to help with this issue @drashna @ibash @abrasive

[github-actions]

Thank you for your contribution!
This pull request has been automatically marked as stale because it has not had activity in the last 45 days. It will be closed in 30 days if no further activity occurs. Please feel free to give a status update now, or re-open when it's ready.
For maintainers: Please label with bug, awaiting review, breaking_change, in progress, or on hold to prevent the issue from being re-flagged.

[ibash]

Hi @NilsIrl sorry for the delay.

The raise keyboard firmware is a fork of keyboardio, so whatever is done for that keyboard should probably be done for the raise too.
Unfortunately I no longer have a dygma raise so can't help validate this.