[clang-tools-extra] [clang-doc] Do not serialize empty text comments (PR #169087)

[Paul Kirth via cfe-commits]

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@@ -100,8 +105,29 @@ static void insertComment(Object &Description, json::Value &Comment,
 
 static json::Value extractTextComments(Object *ParagraphComment) {
   if (!ParagraphComment)
-    return json::Object();
-  return *ParagraphComment->get("Children");
+    return nullptr;
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ilovepi wrote:

Is `nullptr` a valid `json::Value`? I'd have thought we need to return `json::Value::Null` instead.

https://github.com/llvm/llvm-project/pull/169087