Enable log macros to work with no args (#4475)

This is enabled by the C++20 __VA_OPT__ feature.
Uses of "{}" format string were updated.
Some warning suppressions were required for older clang versions.
Also improve codegen of wpi::Logger::Log(), frc::ReportError(), and frc::MakeError();
these generate better and less redundant code if they use fmt::string_view for the
format string instead of templating on it.

cscore/src/main/native/cpp/CvSinkImpl.cpp

@@ -110,7 +110,7 @@ void CvSinkImpl::ThreadMain() {
       std::this_thread::sleep_for(std::chrono::seconds(1));
       continue;
     }
-    SDEBUG4("{}", "waiting for frame");
+    SDEBUG4("waiting for frame");
     Frame frame = source->GetNextFrame();  // blocks
     if (!m_active) {
       break;