Add get_charge, set_charge and use_charge aliases

[S-S-X]

We've had technic.get_RE_charge, technic.set_RE_charge and technic.use_RE_charge available for some time (since 2022), those are also used in various mods already.

Around 2024 minetest-mods/technic added technic.get_charge and technic.set_charge which have compatible interface with Technic Plus counterparts.

For consistency would be good to also add technic.use_charge, preferably even attempt to bring last one also to minetest-mods/technic. Function itself is fairly simple, basically just a shortcut wrapper around get/set functions.
Should then probably also prefer technic.get_charge, technic.set_charge and technic.use_charge by replacing their .*_RE.* counterparts in documentation.

This would give significantly better API compatibility for power tools.

[S-S-X]

Examples what I think should be possible afterwards:

SwissalpS/replacer (ATOW @ master)
https://github.com/SwissalpS/replacer/blob/5d5dfc0f2127bb8d257bd4e518acc2aeafba26df/replacer/replacer.lua#L115-L138

- if technic.plus then
- 	replacer.get_charge = technic.get_RE_charge
- 	replacer.set_charge = technic.set_RE_charge
- else
- 	-- technic still stores data serialized, so this is the nearest we get to current standard
- 	function replacer.get_charge(itemstack)
- 		local meta = deserialize(itemstack:get_meta():get_string(''))
- 		if (not meta) or (not meta.charge) then
- 			return 0
- 		end
- 		return meta.charge
- 	end
-
- 	function replacer.set_charge(itemstack, charge, maximum)
- 		technic.set_RE_wear(itemstack, charge, maximum)
- 		local meta = itemstack:get_meta()
- 		local data = deserialize(meta:get_string(''))
- 		if (not data) or (not data.charge) then
- 			data = { charge = 0 }
- 		end
- 		data.charge = charge
- 		meta:set_string('', serialize(data))
- 	end
- end
+ replacer.get_charge = technic.get_charge
+ replacer.set_charge = technic.set_charge

robertxgray/bweapons_modpack (ATOW PR on mt-historical fixing technic compatibility)
https://github.com/robertxgray/bweapons_modpack/blob/8bfce6db0eb6ea1ee7a767a601306b5423fe889b/bweapons_api/api.lua#L412-L444
Following diff ignores charge migration but so did minetest-mods Technic.
Technic Plus Beta does not need migration at all as there's magic ingredients.

  -- Technic Plus
  if technic.use_charge ~= nil then
  	if not technic.use_charge(itemstack, technic_charge_per_use) then
  		reload = true
  	end
  else
- 	-- Technic Plus
- 	local meta = itemstack:get_meta()
- 	local old_metadata = minetest.deserialize(meta:get_string(""))
- 	local charge = nil
+ 	local charge = technic.get_charge(itemstack)
- 	if old_metadata then
- 		charge = old_metadata.charge
- 	end
- 	-- Technic
- 	if not charge then
- 		charge = meta:get_int("technic:charge")
- 	end
- 
  	if charge < technic_charge_per_use then
  		reload = true
- 	else
- 		if not technic.creative_mode then
+ 	elseif not technic.creative_mode then
- 			charge = charge - technic_charge_per_use
- 			technic.set_RE_wear(itemstack, charge, technic_charge)
- 			if old_metadata and old_metadata.charge then
- 				old_metadata.charge = charge
- 				meta:set_string("", minetest.serialize(old_metadata))
- 			else
- 				meta:set_int("technic:charge", charge)
- 			end
- 		end
+ 		technic.set_charge(itemstack, charge - technic_charge_per_use)
	end
end