[llvm] [Support] Use an inherited constructor in DOTGraphTraits (NFC) (PR #164056)

[Jakub Kuderski via llvm-commits]

================
@@ -164,7 +164,7 @@ struct DefaultDOTGraphTraits {
 ///
 template <typename Ty>
 struct DOTGraphTraits : public DefaultDOTGraphTraits {
-  DOTGraphTraits (bool simple=false) : DefaultDOTGraphTraits (simple) {}
+  using DefaultDOTGraphTraits::DefaultDOTGraphTraits;
----------------
kuhar wrote:

BTW the `public` above is redundant

https://github.com/llvm/llvm-project/pull/164056