Fix typo in docstring

Author: Julfried

pylint/pyreverse/writer.py

@@ -59,8 +59,8 @@ def should_show_node(self, qualified_name: str, is_class: bool = False) -> bool:
 
  Depth is calculated by counting dots in the qualified name:
  - depth 0: top-level packages (no dots)
- - depth 1: first level subpackages (one dot)
- - depth 2: second level subpackages (two dots)
+ - depth 1: first level sub-packages (one dot)
+ - depth 2: second level sub-packages (two dots)
 
  For classes, depth is measured from their containing module, excluding
  the class name itself from the depth calculation.