minor #12623 Update profiler.rst (noniagriconomie)

This PR was submitted for the master branch but it was merged into the 4.3 branch instead (closes #12623).

Discussion
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Update profiler.rst

No need to add the header `Symfony-Debug-Toolbar-Replace` if the request is not an ajax one

Commits
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27f7029 Update profiler.rst

Author: OskarStark

profiler.rst

@@ -206,6 +206,11 @@ event::
         if (!$this->getKernel()->isDebug()) {
             return;
         }
+        
+        $request = $event->getRequest();
+        if (!$request->isXmlHttpRequest()) {
+            return;
+        }
 
         $response = $event->getResponse();
         $response->headers->set('Symfony-Debug-Toolbar-Replace', 1);