fix: document best-effort log chmod

Signed-off-by: memleakd <121398829+memleakd@users.noreply.github.com>

Author: memleakd

system/Log/Handlers/FileHandler.php

@@ -19,7 +19,7 @@
 /**
  * Log error messages to file system
  *
- * @see \CodeIgniter\Log\Handlers\FileHandlerTest
+ * @see FileHandlerTest
  */
 class FileHandler extends BaseHandler
 {
@@ -121,6 +121,7 @@ public function handle($level, $message): bool
         fclose($fp);
 
         if ($newfile) {
+            // The log entry is already persisted - permission changes are best-effort.
             @chmod($filepath, $this->filePermissions);
         }