sponsors: use old logo for dark-mode

Author: justinmk

index.html

@@ -87,7 +87,7 @@ <h2 id="sponsors-header">Sponsors</h2>
               <!-- light mode: -->
               <!-- <source srcset="images/sponsors/coderabbit-logo.svg" media="(prefers-color-scheme: light)"/> -->
               <!-- dark mode: -->
-              <!-- <source srcset="images/sponsors/coderabbit-logo-dark.svg"  media="(prefers-color-scheme: dark)"/> -->
+              <source srcset="images/sponsors/coderabbit-logo-dark.svg"  media="(prefers-color-scheme: dark)"/>
               <!-- no color preference: -->
               <img width="340" class="img-fluid" src="images/sponsors/coderabbit-logo.png">
             </picture>