add new line at end of file, fix compiler warnings

include/spdlog/details/circular_q.h

@@ -59,4 +59,4 @@ private:
     std::vector<T> v_;
 };
 } // namespace details
-} // namespace spdlog
+} // namespace spdlog

include/spdlog/details/fmt_helper.h

@@ -138,4 +138,4 @@ inline void pad6(size_t n, fmt::basic_memory_buffer<char, Buffer_Size> &dest)
 
 } // namespace fmt_helper
 } // namespace details
-} // namespace spdlog
+} // namespace spdlog

include/spdlog/details/thread_pool.h

@@ -216,4 +216,4 @@ private:
 };
 
 } // namespace details
-} // namespace spdlog
+} // namespace spdlog