Linter Introduction + Cleanup (#8085)

* Adds linter defines to repo.

* Uncomments linter defines already in the code.

* Resolves unreachable code linter errors.

* Nukes decade+ old syndie specops code except for computer since that's mapped in?????

* Resolves procs has no parent linter error.

* Proc signature fixes

* Bad comments

* "In" danger

* Type safety

* Implied nested list abuse

* Top level ..() usage

* Sleepy coder typos

* Invalid kwargs calls

* Pointless returns

* Linter hacks (see full message)

Byond doesn't care and it has no effect but linter doesn't like var/proc
for holding references to procs, despite that it's valid byond code.

Also, the linter seems to have serious issues figuring out relative
proc names. This commit is a sort of take-it-or-leave-it thing. It's not
required, it just cuts down on warnings, but this code is valid DM code.

* WHATEVER THIS IS

* Trick dreamchecker linter into ignoring this file's sins in it's weird use of vars

* Fix list decoration syntax - Its a list, not list of lists

- To declare that a var is a list you can `var/list/blah = list()` syntax or the `var/blah[0]` syntax.  Both do exactly the same thing. But if you do `var/list/blah[0]` that is just like doing `var/list/list/blah = list()`

* Hopefully stops the ai holder subtype folder from going quantum and sometimes changes capitalization over time, and incidentally causing 20+ linter errors.

* Fixes unwrapped negated object in list linter error.

* Resolves colon-like list accessing linter error.

* Turns linter on in linter config.

* Fixes closet indentation properly and cleans up suit storage unit switch.

Co-authored-by: Aronai Sieyes <arokha@arokha.com>
Co-authored-by: Leshana <Leshana@users.noreply.github.com>

code/modules/admin/verbs/diagnostics.dm

@@ -17,7 +17,7 @@
 	var/inactive_on_main_station = 0
 	for(var/zone/zone in air_master.zones)
 		var/turf/simulated/turf = locate() in zone.contents
-		if(turf && turf.z in using_map.station_levels)
+		if(turf?.z in using_map.station_levels)
 			if(zone.needs_update)
 				active_on_main_station++
 			else
@@ -79,7 +79,7 @@
 	var/output = "<b>Radio Report</b><hr>"
 	for (var/fq in radio_controller.frequencies)
 		output += "<b>Freq: [fq]</b><br>"
-		var/list/datum/radio_frequency/fqs = radio_controller.frequencies[fq]
+		var/datum/radio_frequency/fqs = radio_controller.frequencies[fq]
 		if (!fqs)
 			output += "&nbsp;&nbsp;<b>ERROR</b><br>"
 			continue