Draft: Make Muon::TileID formattable with fmtlib

LCG 103a will have fmtlib 10 which is more picky than previous versions.

This MR implements a simple fmtlib customization for Muon::TileID needed to build Run2Support and Boole with LCG 103a.

Note: this is part of a pool related (not interdependent MRs), LHCb!4143 (merged), Run2Support!46 (merged), !397 (closed)

Core/include/Core/Utils.h

@@ -14,7 +14,7 @@
 #include <string>
 #include <yaml-cpp/yaml.h>
 
-#if __cplusplus > 201703L && __has_include( <source_location> )
+#if __cplusplus > 201703L && __has_include( <source_location> ) && ! defined( __CLING__ )
 #  include <source_location>
 namespace LHCb::Detector {
   using std::source_location;