Revert "Fix buttons on docs root (#2369)"

This reverts commit d26751a.

docs/source/index.mdx

@@ -4,28 +4,21 @@ sidebar_title: Introduction
 description: A strongly-typed, caching GraphQL client for iOS, written in Swift
 ---
 
-import { Link } from 'gatsby';
-
 **Apollo iOS** is an [open-source](https://github.com/apollographql/apollo-ios) GraphQL client for native iOS apps, written in Swift. It enables you to execute queries and mutations against a GraphQL server and returns results as operation-specific Swift types.
 
 <p>
-  <Button
+  <ButtonLink
     colorScheme="indigo"
-    to="/ios/tutorial/tutorial-introduction/"
-    as={Link}
-    style={{
-      marginRight: '10px'
-    }}
+    href="./tutorial/tutorial-introduction/"
+    mr="4"
   >
     Start the tutorial
-  </Button>
-  <Button
-    colorScheme="gray"
-    to="/ios/installation/"
-    as={Link}
+  </ButtonLink>
+  <ButtonLink
+    href="./installation/"
   >
     Installation
-  </Button>
+  </ButtonLink>
 </p>
 
 ## Benefits