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.

wpilibNewCommands/src/main/native/cpp/frc2/command/CommandGroupBase.cpp

@@ -9,7 +9,7 @@ using namespace frc2;
 bool CommandGroupBase::RequireUngrouped(const Command& command) {
   if (command.IsGrouped()) {
     throw FRC_MakeError(
-        frc::err::CommandIllegalUse, "{}",
+        frc::err::CommandIllegalUse,
         "Commands cannot be added to more than one CommandGroup");
   }
   return true;
@@ -27,7 +27,7 @@ bool CommandGroupBase::RequireUngrouped(
   }
   if (!allUngrouped) {
     throw FRC_MakeError(
-        frc::err::CommandIllegalUse, "{}",
+        frc::err::CommandIllegalUse,
         "Commands cannot be added to more than one CommandGroup");
   }
   return allUngrouped;
@@ -41,7 +41,7 @@ bool CommandGroupBase::RequireUngrouped(
   }
   if (!allUngrouped) {
     throw FRC_MakeError(
-        frc::err::CommandIllegalUse, "{}",
+        frc::err::CommandIllegalUse,
         "Commands cannot be added to more than one CommandGroup");
   }
   return allUngrouped;