Wraps lowertext() to ensure proper stringification. (#82442)

## About The Pull Request

Fixes #82440

This PR just creates a new macro, `LOWER_TEXT()` (yes the irony is not
lost on me) to wrap around all calls of `lowertext()` and ensure that
whatever we input into that proc will be stringified using the `"[]"`
(or `tostring()` for the nerds) operator. very simple.

I also added a linter to enforce this (and prevent all forms of
regression) because I think that machines should do the menial work and
we shouldn't expect maintainers to remember this, let me know if you
disagree. if there is a time when it should be opted out for some
reason, the linter does respect it if you wrap your input with the
`UNLINT()` function.

code/modules/modular_computers/file_system/programs/atmosscan.dm

@@ -44,7 +44,7 @@
 	var/list/airs = islist(mixture) ? mixture : list(mixture)
 	var/list/new_gasmix_data = list()
 	for(var/datum/gas_mixture/air as anything in airs)
-		var/mix_name = capitalize(lowertext(target.name))
+		var/mix_name = capitalize(LOWER_TEXT(target.name))
 		if(airs.len != 1) //not a unary gas mixture
 			mix_name += " - Node [airs.Find(air)]"
 		new_gasmix_data += list(gas_mixture_parser(air, mix_name))

code/modules/modular_computers/file_system/programs/secureye.dm

@@ -70,7 +70,7 @@
 	// Convert networks to lowercase
 	for(var/i in network)
 		network -= i
-		network += lowertext(i)
+		network += LOWER_TEXT(i)
 	// Initialize map objects
 	cam_screen = new
 	cam_screen.generate_view(map_name)