Add Nuer language (nus)

Requested at https://translatewiki.net/wiki/Support ,
but I cannot link to the request as it had to be
deleted because of a LiquidThreads bug.

data/langdb.yaml

@@ -433,6 +433,7 @@ languages:
   nr: [Latn, [AF], isiNdebele seSewula]
   nrm: [Latn, [EU], Nouormand]
   nso: [Latn, [AF], Sesotho sa Leboa]
+  nus: [Latn, [AF], Thok Naath]
   nv: [Latn, [AM], Diné bizaad]
   ny: [Latn, [AF], Chi-Chewa]
   nys: [Latn, [PA], Nyungar]

data/language-data.json

@@ -2787,6 +2787,13 @@
             ],
             "Sesotho sa Leboa"
         ],
+        "nus": [
+            "Latn",
+            [
+                "AF"
+            ],
+            "Thok Naath"
+        ],
         "nv": [
             "Latn",
             [
@@ -5784,7 +5791,8 @@
         ],
         "SS": [
             "ar",
-            "en"
+            "en",
+            "nus"
         ],
         "ST": [
             "pt"
@@ -6039,4 +6047,4 @@
             "tn"
         ]
     }
-}
+}