engine/routines/ stores isolated out-of-context routines as individual files. It might be preferable later to append them to their related engine/ files in unique little SECTIONs, relying on the linkerscript to place them appropriately; or some other organization method. In the meantime, they're now easily findable apart from main.asm's other content.
The former is arguably misleading (as you don’t access the memory location in hl to retrieve the jump location), and is consequently deprecated in newer versions of rgbds.
This fix silences these deprecation warnings.
