Makes Key Lock accessible from code enabling Locking Modifiers #22206

[brotheramai]

Description

Adds begin_key_lock() which mimics pressing QK_LOCK since tap_code does not accept QK_LOCK and tap_code16 exhibits strange behavior when QK_LOCK is passed (on my machine it types 11).
Adds get_key_lock_begun() which returns whether Key Lock is watching for a key to be locked.
Adds get_key_lock_state() which can be passed a keycode and returns its current lock state.

These combined allow for keymap code that can interact with Key Lock to, for example, make specific modifiers toggle like CAPS LOCK when pressed. See examples section of doc for specifics.

Types of Changes

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

Issues Fixed or Closed by This PR

These are all already closed, but would be at least partially addressed by this PR.

• [Feature Request] Locking modifier #22206
• [Feature Request] one shot mod like control over key lock #23001
• Toggle modifier key #25783

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).

[zvecr]

Suggested change

	}
	}

[zvecr]

Suggested change

	void key_lock_start(void);
	void key_lock_start(void);
	void key_lock_cancel(void);

[zvecr]

Suggested change

	void cancel_key_lock(void);
	// DEPRECATED
	#define cancel_key_lock key_lock_cancel

[zvecr]

Suggested change

	void cancel_key_lock(void) {
	void key_lock_cancel(void) {

[zvecr]

Suggested change

	|begin_key_lock() |Begins the key lock sequence. Mimics pressing QK_LOCK |
	|cancel_key_lock() |Cancels the key lock sequnec if called before a lockable key is pressed|
	|get_key_lock_begun()|Checks whether the key lock sequence has started |
	|get_key_lock_state()|Checks whether a specific key is locked |
	|key_lock_start() |Begins the key lock sequence. Mimics pressing QK_LOCK |
	|key_lock_cancel() |Cancels the key lock sequnec if called before a lockable key is pressed|
	|key_lock_active() |Checks whether the key lock sequence has started |
	|key_lock_get_state()|Checks whether a specific key is locked |

[brotheramai]

How do you typically handle announcing deprecations? Should we add a bit to the row for key_lock_cancel explaining that the cancel_key_lock alias has been deprecated and should be updated?

[zvecr]

Given the feature is fairly low use, and the proposed backwards compatibility, its probably not worth adding anything to the docs. We can add something to breaking changes page to cover this.

[zvecr]

Suggested change

	```c
	bool pre_process_record_user(uint16_t keycode, keyrecord_t *record) {
	if (keycode == KC_RCTL || keycode == KC_RSFT || keycode == KC_RALT) {
	if (!key_lock_get_state(keycode) && !key_lock_active()) {
	key_lock_start(); // emulates pressing QK_LOCK when needed