fix: add trailing slashes to sitemap URLs

Ensure sitemap loc entries use Cloudflare's canonical trailing-slash page URLs so crawlers do not pay for redirect hops on every route.

Author: jderochervlk

__tests__/Sitemap_.test.res

@@ -12,10 +12,10 @@ test("renders sorted unique sitemap URLs with a normalized base URL", async () =
     <loc>https://preview.example.com/</loc>
   </url>
   <url>
-    <loc>https://preview.example.com/blog</loc>
+    <loc>https://preview.example.com/blog/</loc>
   </url>
   <url>
-    <loc>https://preview.example.com/docs/manual/introduction</loc>
+    <loc>https://preview.example.com/docs/manual/introduction/</loc>
   </url>
 </urlset>
 `)

src/common/Sitemap.res

@@ -49,8 +49,16 @@ let normalizePaths = paths =>
     }
   })
 
+let withTrailingSlash = path => {
+  if path === "/" || path->String.endsWith("/") {
+    path
+  } else {
+    path ++ "/"
+  }
+}
+
 let renderUrl = (~baseUrl, path) => {
-  let loc = baseUrl ++ path
+  let loc = baseUrl ++ path->withTrailingSlash
 
   `  <url>
     <loc>${loc->escapeXml}</loc>