[llvm] [MsgPack] Return an Error instead of bool from readFromBlob (PR #74357)

[Alexander Richardson via llvm-commits]

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@@ -187,7 +186,9 @@ bool Document::readFromBlob(
       Node = getArrayNode();
       break;
     default:
-      return false; // Raw and Extension not supported
+      return make_error<StringError>(
+          "Raw and Extension not supported",
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arichardson wrote:

Maybe "Unsupported object type"?

https://github.com/llvm/llvm-project/pull/74357