[MIRROR] Document managed globals (#2441)

Co-authored-by: SierraKomodo <[email protected]>

code/__datastructures/globals.dm

@@ -1,7 +1,9 @@
-/* *
-* Managed Globals
-*/
-
+/**
+ * Managed Globals datum. Any defined global vars can be accessed via `GLOB.varname`.
+ *
+ * New globals can be defined on the global scope (Outside of any class definitions) via the various `GLOBAL_*()`
+ * defines listed at the end of `code\__datastructures\globals.dm`.
+ */
 var/global/datum/globals/GLOB
 
 
@@ -62,20 +64,28 @@ var/global/datum/globals/GLOB
 	##X = V; \
 }
 
+/// Initializes the global constant `GLOB.[X]` with the value `[V]` as a managed global.
 #define GLOBAL_VAR_CONST(X, V) /datum/globals/var/const/##X = V;
 
+/// Initializes the global variable `GLOB.[X]` with no value (`null`) as a managed global.
 #define GLOBAL_VAR(X) /datum/globals/var/static/##X;
 
+/// Initializes the global variable `GLOB.[X]` with the value `[V]` as a managed global.
 #define GLOBAL_VAR_INIT(X, V) GLOBAL_VAR(X) GLOBAL_INIT(X, V)
 
+/// Initializes the global variable `GLOB.[X]` as an instance of `/static[P]` with no value (`null`) as a managed global.
 #define GLOBAL_DATUM(X, P) /datum/globals/var/static##P/##X;
 
+/// Initializes the global variable `GLOB.[X]` as an instance of `/static[P]` with the value `[V]` as a managed global.
 #define GLOBAL_DATUM_INIT(X, P, V) GLOBAL_DATUM(X, P) GLOBAL_INIT(X, V)
 
+/// Initializes the global variable `GLOB[X]` as a list with no value (`null`) as a managed global.
 #define GLOBAL_LIST(X) /datum/globals/var/static/list/##X;
 
+/// Initializes the global variable `GLOB[X]` as a list with value `[V]` as a managed global.
 #define GLOBAL_LIST_INIT(X, V) GLOBAL_LIST(X) GLOBAL_INIT(X, V)
 
+/// Initializes the global variable `GLOB[X]` as an empty list (`list()`) as a managed global.
 #define GLOBAL_LIST_EMPTY(X) GLOBAL_LIST_INIT(X, list())
 
 /// Prevents the GLOB member from being shown in View Variables.