Enhance git fetch error: include error on page if possible

settings_update.php

@@ -24,7 +24,7 @@ $git_log = shell_exec("git log $repo_branch..origin/$repo_branch --pretty=format
         </div>
         <div class="card-body" style="text-align: center;">
 
-            <!-- Check if git fetch result is zero (success) -->
+            <!-- Check if git fetch result was successful (0), if not show a warning -->
             <?php if ($result !== 0) { ?>
                 <div class="alert alert-danger" role="alert">
                     <strong>WARNING: Could not find execute 'git fetch'.</strong>