Some cleanup and tests for Enum and constexpr strings.

ConstexprString.h

@@ -24,6 +24,11 @@ namespace Alepha::Hydrogen  ::detail::  ConstexprString_m
 		// benefit of the NTTP variadic list way, for compiler memory usage, is that
 		// the a type using the string as a parameter has a symbol size which
 		// is proportional to the number of chars in the string.
+		//
+		// However, NTTP parameters are pretty large in terms of memory footprint
+		// of the compiler and they do tax the compiler's CPU usage a lot more.
+		// As such, compile time strings of a "reasonable" size are probably the
+		// best we can hope for.
 		const std::size_t maxSize= 128;
 	}
 
@@ -47,7 +52,7 @@ namespace Alepha::Hydrogen  ::detail::  ConstexprString_m
 					const char *
 					what() const noexcept final
 					{
-						return "Failure  to allocate enough space for a a compile-time string.";
+						return "Failure to allocate enough space for a a compile-time string.";
 					}
 			};