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.

wpilibc/src/main/native/cpp/counter/ExternalDirectionCounter.cpp

@@ -24,10 +24,10 @@ ExternalDirectionCounter::ExternalDirectionCounter(
     std::shared_ptr<DigitalSource> countSource,
     std::shared_ptr<DigitalSource> directionSource) {
   if (countSource == nullptr) {
-    throw FRC_MakeError(err::NullParameter, "{}", "countSource");
+    throw FRC_MakeError(err::NullParameter, "countSource");
   }
   if (directionSource == nullptr) {
-    throw FRC_MakeError(err::NullParameter, "{}", "directionSource");
+    throw FRC_MakeError(err::NullParameter, "directionSource");
   }
 
   m_countSource = countSource;