Add Diffs features to the New Diffs blueprint

doc/architecture/blueprints/new_diffs/features.md

+---
+status: proposed
+creation-date: "2023-10-10"
+authors: [ "@thomasrandolph", "@patrickbajao", "@igor.drozdov", "@jerasmus", "@iamphill", "@slashmanov", "@psjakubowska" ]
+coach: [ "@ntepluhina" ]
+approvers: [ ]
+owning-stage: "~devops::create"
+participating-stages: []
+---
+
+This is an appendix to the [New Diffs document](index.md).
+
+# Diffs features
+
+Below is a complete list of features for merge request and commit diffs grouped by diff viewers (Code, Image, Other).
+
+✓ – available in both MR and Commit views.
+
+| Features                          | Code   | Image | Other |
+|-----------------------------------|--------|-------|-------|
+| Filename                          | ✓      | ✓     | ✓     |
+| Copy file path                    | ✓      | ✓     | ✓     |
+| Collapse and expand file          | ✓      | ✓     | ✓     |
+| File stats                        | ✓      | ✓     | ✓     |
+| Lines changed (0 for blobs)       | ✓      | ✓     | ✓     |
+| Permissions changed               | ✓      | ✓     | ✓     |
+| CRUD comment on file              | ✓      | ✓     | ✓     |
+| View file link                    | ✓      | ✓     | ✓     |
+| Mark as viewed                    | MR     | MR    | MR    |
+| Hide all comments                 | MR     | MR    | MR    |
+| Show full file (expand all lines) | MR     |       |       |
+| Open in Web IDE link              | MR     |       |       |
+| Line link                         | ✓      |       |       |
+| Edit file link                    | ✓      |       |       |
+| Code highlight (multiple themes)                    | ✓      |       |       |
+| Expand lines                      | ✓      |       |       |
+| CRUD comment on specific line     | Commit      |       |       |
+| CRUD comment on line range        | MR      |       |       |
+| Draft comment on line range       | MR      |       |       |
+| Code quality highlights           | ✓      |       |       |
+| Test coverage highlights          | ✓      |       |       |
+| Hide whitespace changes           | ✓      |       |       |
+| Auto-collapse large file          | ✓      |       |       |
+| View as raw                       | Commit |       |       |
+| Side by side view                 |        | ✓     |       |

doc/architecture/blueprints/new_diffs/index.md

@@ -20,6 +20,8 @@ to develop a single, performant way for diffs to be rendered across the applicat
 to improve all areas of diff rendering, from the backend creation of diffs to the frontend rendering
 the diffs.
 
+All the diffs features related to this document are [listed on a dedicated page](features.md).
+
 ## Motivation
 
 ### Goals