Repository: syncthing/syncthing (language: go)

Issue:
gui: Favicon not working in Firefox bookmarks
### What happened?

Firefox doesn't show any favicon at all when adding a bookmark to the Syncthing GUI, even with the static favicon introduced by #8850. It looks like Firefox prefers the last favicon that is found in `<head>` which is the link to `favicon-{{syncthingStatus()}}.png`. Because that file is not available on initial page load, it is not considered for bookmarks. The favicon logic for Firefox can be found [here](https://searchfox.org/mozilla-central/rev/c09764753ea40725eb50decad2c51edecbd33308/browser/modules/FaviconLoader.sys.mjs#443).
Switching the order of the favicon links in `<head>` fixes the behavior for Firefox while breaking the dynamic favicon for Chromium-based browsers.
A proper fix for this issue was suggested by @ajshea in https://github.com/syncthing/syncthing/issues/7638#issuecomment-838888561.

### Syncthing version

v1.27.6

### Platform & operating system

Linux x86

### Browser version

Firefox 124.0.2

### Relevant log output

_No response_


Discussion / hints:

Fix patch:
diff --git a/gui/default/index.html b/gui/default/index.html
index 0565f567dc3..d0aee77d1e9 100644
--- a/gui/default/index.html
+++ b/gui/default/index.html
@@ -12,8 +12,7 @@
   <meta charset="utf-8"/>
   <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
   <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
-  <link rel="shortcut icon" href="assets/img/favicon-default.png" type="image/x-icon"/>
-  <link rel="shortcut icon" href="assets/img/favicon-{{syncthingStatus()}}.png" type="image/x-icon"/>
+  <link rel="shortcut icon" href="assets/img/favicon-default.png" ng-href="assets/img/favicon-{{syncthingStatus()}}.png" type="image/x-icon"/>
   <link rel="mask-icon" href="assets/img/safari-pinned-tab.svg" color="#0882c8"/>
 
   <title ng-bind="thisDeviceName() + ' | Syncthing'"></title>


Test patch: