Count .png and .woff2 as shared files

These used to be served by the database handler. Now that it no longer
exists, handle them in the shared resource handler directly.

src/web/rustdoc.rs

@@ -646,7 +646,10 @@ impl Handler for SharedResourceHandler {
         let path = req.url.path();
         let filename = path.last().unwrap(); // unwrap is fine: vector is non-empty
         if let Some(extension) = Path::new(filename).extension() {
-            if ["js", "css", "woff", "svg"].iter().any(|s| *s == extension) {
+            if ["js", "css", "woff", "woff2", "svg", "png"]
+                .iter()
+                .any(|s| *s == extension)
+            {
                 let storage = extension!(req, Storage);
                 let config = extension!(req, Config);