Add more detailed comment explaining the force recompile hack.

spirv_msl.cpp

@@ -18167,6 +18167,10 @@ void CompilerMSL::emit_argument_buffer_aliased_descriptor(const SPIRVariable &al
 	}
 	else
 	{
+		// This alias may have already been used to emit an entry point declaration. If there is a mismatch, we need a recompile.
+		// Moving this code to be run earlier will also conflict,
+		// because we need the qualified alias for the base resource,
+		// so forcing recompile until things sync up is the least invasive method for now.
 		if (ir.meta[aliased_var.self].decoration.qualified_alias != name)
 			force_recompile();