Refactor: group kira keyboards (#22760)

data/mappings/keyboard_aliases.hjson

@@ -329,6 +329,12 @@
     "keycapsss/plaid_pad": {
         "target": "keycapsss/plaid_pad/rev1"
     },
+    "kira75": {
+        "target": "kira/kira75"
+    },
+    "kira80": {
+        "target": "kira/kira80"
+    },
     "kudox": {
         "target": "kumaokobo/kudox/rev1"
     },

keyboards/kira/kira75/readme.md

@@ -10,6 +10,6 @@ Hardware Availability: Group Buy
 
 Make example for this keyboard (after setting up your build environment):
 
-    make kira75:default
+    make kira/kira75:default
 
 See [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) then the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information.

keyboards/kira/kira80/readme.md

@@ -11,11 +11,11 @@ Custom TKL keyboard designed and made by Thesiscamper and EVE
 
 Make example for this keyboard (after setting up your build environment):
 
-    make kira80:default
+    make kira/kira80:default
 
 Flashing example for this keyboard ([after setting up the bootloadHID flashing environment](https://docs.qmk.fm/#/flashing_bootloadhid))
 
-    make kira80:default:flash
+    make kira/kira80:default:flash
 
 **Reset Key:** Hold down the key located at `K102`, commonly programmed as 'Pause' while plugging in the keyboard.