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/admin/sql_ban_system.dm

@@ -577,7 +577,7 @@
 	duration = text2num(duration)
 	if (!(interval in list("SECOND", "MINUTE", "HOUR", "DAY", "WEEK", "MONTH", "YEAR")))
 		interval = "MINUTE"
-	var/time_message = "[duration] [lowertext(interval)]" //no DisplayTimeText because our duration is of variable interval type
+	var/time_message = "[duration] [LOWER_TEXT(interval)]" //no DisplayTimeText because our duration is of variable interval type
 	if(duration > 1) //pluralize the interval if necessary
 		time_message += "s"
 	var/is_server_ban = (roles_to_ban[1] == "Server")