Scope margin-bottom to direct child images only, preserving figure caption spacing

Co-authored-by: grst <7051479+grst@users.noreply.github.com>
Agent-Logs-Url: https://github.com/scverse/scverse.github.io/sessions/3f114782-3b08-48a7-8bb1-5f5984a250f6

Author: Copilot

assets/main.scss

@@ -940,7 +940,8 @@ body {
             margin: 3rem 0;
             font-size: 1.1rem;
             text-wrap: pretty;
-            img {
+            > img,
+            > p > img {
                 margin-bottom: 1.5rem;
             }
             span.backticked {