Genericize compat error message

Author: francinum

code/_byond_version_compact.dm

@@ -6,7 +6,7 @@
 #if (DM_VERSION < MIN_COMPILER_VERSION || DM_BUILD < MIN_COMPILER_BUILD) && !defined(SPACEMAN_DMM)
 //Don't forget to update this part
 #error Your version of BYOND is too out-of-date to compile this project. Go to https://secure.byond.com/download and update.
-#error You need version 515.1609 or higher
+#error For a specific minimum version, check code/_byond_version_compact.dm
 #endif
 
 // Keep savefile compatibilty at minimum supported level