API: Return primary language and repository language stats API URL (#18396)

templates/swagger/v1_json.tmpl

@@ -17188,6 +17188,14 @@
         "internal_tracker": {
           "$ref": "#/definitions/InternalTracker"
         },
+        "language": {
+          "type": "string",
+          "x-go-name": "Language"
+        },
+        "languages_url": {
+          "type": "string",
+          "x-go-name": "LanguagesURL"
+        },
         "mirror": {
           "type": "boolean",
           "x-go-name": "Mirror"