Restore method documentation in _get_tool_version

Author: c0dew3ll

wifite/util/system_check.py

@@ -281,6 +281,7 @@ def check_tools(self) -> List[ToolCheckResult]:
         return results
 
     def _get_tool_version(self, name: str) -> Optional[str]:
+        """Try to get version string for a tool."""
         if name == 'airmon-ng':
             if shutil.which(name):
                 return None