[0.12.8] Misspelling "terciary" present in game code

[Supercheese]

In the specs for Prototype/Entity/energy_source/usage_priority, one of the options is "terciary", which is a misspelling of "tertiary" (accumulators and modular armor batteries have this set as their usage priority). This is a very minor spelling issue, but it bugs me each time I glance at the code for accumulators or battery modules.

Files affected:

base\prototypes\entity\entities.lua (in entry for "basic-accumulator")
base\prototypes\equipment\equipment.lua (in entries for "battery-equipment" and "battery-mk2-equipment")