Revert "add trailing slash to app manifest start url"

This reverts commit 84c8396.

pkg/app/http.go

@@ -385,11 +385,6 @@ func (h *Handler) makeManifestJSON() []byte {
 		scope += "/"
 	}
 
-	startURL := h.Resources.Resolve("/")
-	if !strings.HasSuffix(startURL, "/") {
-		startURL += "/"
-	}
-
 	var b bytes.Buffer
 	if err := template.
 		Must(template.New("manifest.webmanifest").Parse(manifestJSON)).
@@ -416,7 +411,7 @@ func (h *Handler) makeManifestJSON() []byte {
 			BackgroundColor: h.BackgroundColor,
 			ThemeColor:      h.ThemeColor,
 			Scope:           scope,
-			StartURL:        startURL,
+			StartURL:        h.Resources.Resolve("/"),
 		}); err != nil {
 		panic(errors.New("initializing manifest.webmanifest failed").Wrap(err))
 	}