docs: update .all-contributorsrc [skip ci]

Author: allcontributors[bot]

.all-contributorsrc

@@ -2019,6 +2019,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "alexwh",
+      "name": "Alex",
+      "avatar_url": "https://avatars.githubusercontent.com/u/1723612?v=4",
+      "profile": "https://github.com/alexwh",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,