gh-148588: Add relative import example to __lazy_modules__ docs

Author: johnslavik

Doc/reference/simple_stmts.rst

@@ -948,7 +948,13 @@ Python versions older than 3.15 while leveraging lazy imports on 3.15+::
    import pathlib  # loaded lazily
 
 Relative imports are resolved to their absolute name before the lookup, so
-the sequence must always contain fully qualified module names.
+the sequence must always contain fully qualified module names::
+
+   # In mypackage/mymodule.py
+   __lazy_modules__ = ["mypackage"]
+
+   from . import utils  # loaded lazily: resolves to mypackage
+   import json          # loaded eagerly (not in __lazy_modules__)
 
 Imports inside functions, class bodies, or
 :keyword:`try`/:keyword:`except`/:keyword:`finally` blocks are always eager,