Add macro for momentarily switching to a layer while some mods are active (#2460)

* Macro for a momentary layer switch with mods

Passes through to the existing ACTION_LAYER_MODS macro, albeit with more
limited options due to lack of space in the quantum_keycodes enum.

* Add documentation for LM layer-mod macro

* Clean up Tap Toggle documentation

1 files changed, 5 insertions, 0 deletions

diff --git a/quantum/keymap_common.c b/quantum/keymap_common.c
index 8b09f93fc..9a412b66a 100644
--- a/quantum/keymap_common.c
+++ b/quantum/keymap_common.c
@@ -122,6 +122,11 @@ action_t action_for_key(uint8_t layer, keypos_t key)
         case QK_LAYER_TAP_TOGGLE ... QK_LAYER_TAP_TOGGLE_MAX:
             action.code = ACTION_LAYER_TAP_TOGGLE(keycode & 0xFF);
             break;
+        case QK_LAYER_MOD ... QK_LAYER_MOD_MAX:
+            mod = keycode & 0xF;
+            action_layer = (keycode >> 4) & 0xF;
+            action.code = ACTION_LAYER_MODS(action_layer, mod);
+            break;
         case QK_MOD_TAP ... QK_MOD_TAP_MAX:
             mod = mod_config((keycode >> 0x8) & 0x1F);
             action.code = ACTION_MODS_TAP_KEY(mod, keycode & 0xFF);