docs: Move more sections under hardware integration (#2704)

docs: Move battery sensing hardware integration to new page

docs: Refactor lighting hardware integrations to new category

docs: Link to pin control page from lighting pages

docs: Consolidate lighting feature pages

docs: Remove incorrect redirect

docs: Consolidate lighting config pages

docs/sidebars.js

@@ -41,8 +41,7 @@ module.exports = {
         "features/encoders",
         "features/pointing",
         "features/displays",
-        "features/backlight",
-        "features/underglow",
+        "features/lighting",
         "features/studio",
       ],
     },
@@ -120,19 +119,18 @@ module.exports = {
       },
       collapsed: true,
       items: [
-        "config/backlight",
         "config/battery",
         "config/behaviors",
         "config/bluetooth",
         "config/combos",
         "config/displays",
         "config/encoders",
+        "config/lighting",
         "config/pointing",
         "config/keymap",
         "config/layout",
         "config/kscan",
         "config/power",
-        "config/underglow",
         "config/system",
         "config/studio",
       ],
@@ -157,6 +155,20 @@ module.exports = {
             "development/hardware-integration/encoders",
             "development/hardware-integration/soft-off-setup",
             "development/hardware-integration/pointing",
+            "development/hardware-integration/battery",
+            {
+              type: "category",
+              label: "Lighting",
+              link: {
+                type: "doc",
+                id: "development/hardware-integration/lighting/index",
+              },
+              collapsed: true,
+              items: [
+                "development/hardware-integration/lighting/underglow",
+                "development/hardware-integration/lighting/backlight",
+              ],
+            },
           ],
         },
         {