✏ Fix line numbers in Python code snippets

Author: daniil-berg

docs/advanced/self-referential.md

@@ -16,10 +16,10 @@ To allow more fine-grained control over it, the `Relationship` constructor allow
 
 Since SQLAlchemy relationships provide the [`remote_side`](https://docs.sqlalchemy.org/en/14/orm/relationship_api.html#sqlalchemy.orm.relationship.params.remote_side){.external-link target=_blank} parameter for just such an occasion, we can leverage that directly to construct the self-referential pattern with minimal code.
 
-```Python hl_lines="15-17"
+```Python hl_lines="12"
 # Code above omitted 👆
 
-{!./docs_src/advanced/self_referential/tutorial001.py[ln:5-21]!}
+{!./docs_src/advanced/self_referential/tutorial001.py[ln:6-17]!}
 
 # Code below omitted 👇
 ```
@@ -57,7 +57,7 @@ Now let us see how we can create villains with a boss:
 ```Python hl_lines="6-7"
 # Code above omitted 👆
 
-{!./docs_src/advanced/self_referential/tutorial001.py[ln:34-51]!}
+{!./docs_src/advanced/self_referential/tutorial001.py[ln:30-47]!}
 
 # Code below omitted 👇
 ```
@@ -78,11 +78,11 @@ If we only learn that a villain actually had a secret boss after we have already
 ```Python hl_lines="8"
 # Code above omitted 👆
 
-{!./docs_src/advanced/self_referential/tutorial001.py[ln:34-35]!}
+{!./docs_src/advanced/self_referential/tutorial001.py[ln:30-31]!}
 
         # Previous code here omitted 👈
 
-{!./docs_src/advanced/self_referential/tutorial001.py[ln:53-57]!}
+{!./docs_src/advanced/self_referential/tutorial001.py[ln:49-53]!}
 
 # Code below omitted 👇
 ```
@@ -98,14 +98,14 @@ If we only learn that a villain actually had a secret boss after we have already
 
 And if we want to add minions to a boss after the fact, this is as easy as adding items to a Python list (because that's all it is 🤓):
 
-```Python hl_lines="11-15"
+```Python hl_lines="11"
 # Code above omitted 👆
 
-{!./docs_src/advanced/self_referential/tutorial001.py[ln:34-35]!}
+{!./docs_src/advanced/self_referential/tutorial001.py[ln:30-31]!}
 
         # Previous code here omitted 👈
 
-{!./docs_src/advanced/self_referential/tutorial001.py[ln:59-74]!}
+{!./docs_src/advanced/self_referential/tutorial001.py[ln:55-66]!}
 
 # Code below omitted 👇
 ```