New feature: PERMISSIVE_HOLD_PER_KEY (#7994)

* Implement 'PERMISSIVE_HOLD_PER_KEY'

* Document 'PERMISSIVE_HOLD_PER_KEY'

Co-authored-by: GeorgeKoenig <35542036+GeorgeKoenig@users.noreply.github.com>

docs/config_options.md

@@ -142,6 +142,8 @@ If you define these options you will enable the associated feature, which may in
 * `#define PERMISSIVE_HOLD`
   * makes tap and hold keys trigger the hold if another key is pressed before releasing, even if it hasn't hit the `TAPPING_TERM`
   * See [Permissive Hold](feature_advanced_keycodes.md#permissive-hold) for details
+* `#define PERMISSIVE_HOLD_PER_KEY`
+  * enabled handling for per key `PERMISSIVE_HOLD` settings
 * `#define IGNORE_MOD_TAP_INTERRUPT`
   * makes it possible to do rolling combos (zx) with keys that convert to other keys on hold, by enforcing the `TAPPING_TERM` for both keys.
   * See [Mod tap interrupt](feature_advanced_keycodes.md#ignore-mod-tap-interrupt) for details

docs/feature_advanced_keycodes.md

@@ -265,6 +265,25 @@ Normally, if you do all this within the `TAPPING_TERM` (default: 200ms) this wil
 
 ?> If you have `Ignore Mod Tap Interrupt` enabled, as well, this will modify how both work. The regular key has the modifier added if the first key is released first or if both keys are held longer than the `TAPPING_TERM`.
 
+For more granular control of this feature, you can add the following to your `config.h`:
+
+```c
+#define PERMISSIVE_HOLD_PER_KEY
+```
+
+You can then add the following function to your keymap:
+
+```c
+bool get_permissive_hold(uint16_t keycode, keyrecord_t *record) {
+  switch (keycode) {
+    case SFT_T(KC_A):
+      return true;
+    default:
+      return false;
+  }
+}
+```
+
 ## Ignore Mod Tap Interrupt
 
 To enable this setting, add this to your `config.h`: