Fix: Last line of code block was wrong

app/Services/Markdown/Linter.php

@@ -187,6 +187,10 @@ private function formatCodeBlock(string $block): string
             $lines[0] = preg_replace('/^(```\w*)\s*{.*?}$/', '$1', trim($lines[0]));
         }
 
+        $last = count($lines) - 1;
+
+        $lines[$last] = '```';
+
         // Reassemble the block
         return implode("\n", $lines);
     }