[clang-tools-extra] [clang-doc] Add a top-level index.html page (PR #171899)

[Paul Kirth via cfe-commits]

================
@@ -318,7 +318,8 @@ serializeCommonAttributes(const Info &I, json::Object &Obj,
 }
 
 static void serializeReference(const Reference &Ref, Object &ReferenceObj) {
-  ReferenceObj["Path"] = Ref.Path;
+  if (!Ref.Path.empty())
+    ReferenceObj["Path"] = Ref.Path;
----------------
ilovepi wrote:

Let's add a comment here about why we're not always setting this.

https://github.com/llvm/llvm-project/pull/171899