[NFC] [llvm] Forward forwarding references

[ccotter]

Summary

Update function bodies to forward forwarding references.
I spotted this while authoring a clang-tidy tool for CppCoreGuideline F.19

[ccotter]

• Add more

[ccotter]

• Fix BitVector

llvm/include/llvm/Support/HashBuilder.h

 //===- llvm/Support/HashBuilder.h - Convenient hashing interface-*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
class HashBuilderImpl : public HashBuilderBase<HasherT> {
   static_assert(Endianness != support::endianness::native,
                 "HashBuilder should canonicalize endianness");
 
 public:
   explicit HashBuilderImpl(HasherT &Hasher)
       : HashBuilderBase<HasherT>(Hasher) {}
   template <typename... ArgTypes>
   explicit HashBuilderImpl(ArgTypes &&...Args)
-      : HashBuilderBase<HasherT>(Args...) {}
+      : HashBuilderBase<HasherT>(std::forward<ArgTypes>(Args)...) {}
 
   /// Implement hashing for hashable data types, e.g. integral or enum values.
   template <typename T>
   std::enable_if_t<hashbuilder_detail::IsHashableData<T>::value,
                    HashBuilderImpl &>
   add(T Value) {
     return adjustForEndiannessAndAdd(Value);
   }