Add Najdi (ars)

Used in MinT.

Autonym according to Ethnologue.

Downstream task: https://phabricator.wikimedia.org/T336683

data/langdb.yaml

@@ -44,6 +44,7 @@ languages:
   arn: [Latn, [AM], mapudungun]
   aro: [Latn, [AM], Araona]
   arq: [Arab, [AF, ME], جازايرية]
+  ars: [Arab, [ME], نجدي]
   ary: [Arab, [AF, ME], الدارجة]
   ary-arab: [ary]
   ary-latn: [Latn, [AF, ME], ed-dārija]

data/language-data.json

@@ -281,6 +281,13 @@
             ],
             "جازايرية"
         ],
+        "ars": [
+            "Arab",
+            [
+                "ME"
+            ],
+            "نجدي"
+        ],
         "ary": [
             "Arab",
             [
@@ -6543,7 +6550,8 @@
             "fr"
         ],
         "SA": [
-            "ar"
+            "ar",
+            "ars"
         ],
         "SB": [
             "en",