Fix changelog icon CSS to only target sidebar links

Updated the CSS selector from 'a[href$="changelog"] svg' to
'.fern-sidebar-link.nested[href$="changelog"] > svg' to specifically
target only the SVG icon within the sidebar changelog link.

This prevents the rule from inadvertently hiding all SVGs on changelog
pages that have links attached to them, while still hiding the changelog
icon in the sidebar navigation as intended.

Co-Authored-By: Kapil Gowru <[email protected]>

Author: devin-ai-integration[bot]

fern/assets/styles.css

@@ -1104,6 +1104,6 @@ h1, h2, h3 {
 /*** END -- FERN EDITOR STYLING ***/
 
 /* HACK: hide the changelog icon for changelog pages */
-a[href$="changelog"] svg {
+.fern-sidebar-link.nested[href$="changelog"] > svg {
   display: none;
-}
+}