misc: chore: [ci skip] forgot to make that a locale entry

src/Ryujinx/Assets/locales.json

@@ -7747,6 +7747,31 @@
         "zh_TW": ""
       }
     },
+    {
+      "ID": "ControllerSettingsLedColorRainbowSpeed",
+      "Translations": {
+        "ar_SA": "",
+        "de_DE": "",
+        "el_GR": "",
+        "en_US": "Rainbow Speed",
+        "es_ES": "",
+        "fr_FR": "",
+        "he_IL": "",
+        "it_IT": "",
+        "ja_JP": "",
+        "ko_KR": "",
+        "no_NO": "",
+        "pl_PL": "",
+        "pt_BR": "",
+        "ru_RU": "",
+        "sv_SE": "",
+        "th_TH": "",
+        "tr_TR": "",
+        "uk_UA": "",
+        "zh_CN": "",
+        "zh_TW": ""
+      }
+    },
     {
       "ID": "ControllerSettingsLedColor",
       "Translations": {

src/Ryujinx/UI/Views/Input/LedInputView.axaml

@@ -28,7 +28,7 @@
             </CheckBox>
         </StackPanel>
         <StackPanel Orientation="Horizontal" IsEnabled="{Binding !TurnOffLed}">
-            <TextBlock MinWidth="75" MaxWidth="200" Text="Rainbow Speed" />
+            <TextBlock MinWidth="75" MaxWidth="200" Text="{ext:Locale ControllerSettingsLedColorRainbowSpeed}" />
             <Slider HorizontalAlignment="Center" 
                     Value="{Binding RainbowSpeed}"
                     Width="175"