Fixup the gitbook config

book.json

@@ -5,6 +5,12 @@
     "plugins" : [
       "anchors",
       "edit-link",
+      "etoc",
+      "forkmegithub",
+      "git-author",
+      "hints",
+      "numbered-headings",
+      "terminal",
       "toolbar"
     ],
     "pluginsConfig": {
@@ -12,6 +18,14 @@
         "base": "https://github.com/qmk/qmk_firmware/edit/master/docs",
         "label": "Suggest an edit"
       },
+      "forkmegithub": {
+        "color": "red",
+        "url": "https://github.com/qmk/qmk_firmware"
+      },
+      "etoc": {
+        "maxdepth": 3,
+        "notoc": true
+      },
       "toolbar": {
         "buttons": [
           {