adding redirects for missing links

docs/packages-ref.json

@@ -0,0 +1,3 @@
+{
+    "redirect": "/extensions"
+}

docs/packages/approval-ref.json

@@ -0,0 +1,3 @@
+{
+    "redirect": "https://makecode.com/extensions/approval"
+}

docs/packages/build-your-own-ref.json

@@ -0,0 +1,3 @@
+{
+    "redirect": "https://makecode.com/extensions/build-your-own"
+}

docs/packages/versioning-ref.json

@@ -0,0 +1,3 @@
+{
+    "redirect": "https://makecode.com/extensions/versioning"
+}