Modular computers changes (#19928)

* Fixes and documentation.

* WIp on laptop vendor

* some fixes

code/modules/modular_computers/hardware/processor_unit.dm

@@ -41,6 +41,8 @@
 	origin_tech = list("programming" = 4, "engineering" = 3)
 
 /obj/item/weapon/computer_hardware/processor_unit/try_install_component(mob/living/user, obj/item/modular_computer/M, found = 0)
+	if(!user.drop_item(src))
+		return
 	if(M.processor_unit)
 		user << "This computer's processor slot is already occupied by \the [M.processor_unit]."
 		return