fix: Use comments for group headers in custom format listing

CHANGELOG.md

@@ -8,6 +8,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- Category headers in `--list-custom-formats` output is now formatted as a YAML comment that can be
+  copied with the list of Trash IDs.
+
 ## [4.0.2] - 2022-12-26
 
 ### Changed

src/Recyclarr.TrashLib/Services/Common/GuideDataLister.cs

@@ -24,7 +24,7 @@ public class GuideDataLister : IGuideDataLister
         foreach (var cat in categories)
         {
             var title = cat.Key is not null ? $"{cat.Key}" : "[No Category]";
-            _console.Output.WriteLine($"\n{title}\n");
+            _console.Output.WriteLine($"\n          # {title}");
 
             foreach (var cf in cat)
             {