doc: fix favicon url

Author: victorpoughon

docs/src/.vitepress/config.mts

@@ -7,7 +7,7 @@ import version from "vite-plugin-package-version";
 export default defineConfig({
   title: "Torch Lens Maker",
   description: "Differentiable geometric optics in PyTorch",
-  head: [['link', { rel: 'icon', href: '/logos/tlmlogo_black130_margin.png' }]],
+  head: [['link', { rel: 'icon', href: '/torchlensmaker/logos/tlmlogo_black130_margin.png' }]],
   base: '/torchlensmaker/',
   themeConfig: {
     logo: '/logos/tlmlogo_black150.png',