Make RandomMetadata properly support localization (#36343)

* Make _outputSegments readonly

* Remove mystery character

* Use Fluent instead of string concatenation

* Adjust format

* Convert existing content

* Don't need these anymore

* Docs

Content.Server/RandomMetadata/RandomMetadataComponent.cs

@@ -1,7 +1,7 @@
 using Content.Shared.Dataset;
 using Robust.Shared.Prototypes;
 
-namespace Content.Server.RandomMetadata;
+namespace Content.Server.RandomMetadata;
 
 /// <summary>
 ///     Randomizes the description and/or the name for an entity by creating it from list of dataset prototypes or strings.
@@ -15,9 +15,17 @@ public sealed partial class RandomMetadataComponent : Component
     [DataField]
     public List<ProtoId<LocalizedDatasetPrototype>>? NameSegments;
 
+    /// <summary>
+    /// LocId of the formatting string to use to assemble the <see cref="NameSegments"/> into the entity's name.
+    /// Segments will be passed to the localization system with this string as variables named $part0, $part1, $part2, etc.
+    /// </summary>
     [DataField]
-    public string NameSeparator = " ";
+    public LocId NameFormat = "random-metadata-name-format-default";
 
+    /// <summary>
+    /// LocId of the formatting string to use to assemble the <see cref="DescriptionSegments"/> into the entity's description.
+    /// Segments will be passed to the localization system with this string as variables named $part0, $part1, $part2, etc.
+    /// </summary>
     [DataField]
-    public string DescriptionSeparator = " ";
+    public LocId DescriptionFormat = "random-metadata-description-format-default";
 }