Remove "See Note" mentions from docstrings

These notes are for internal use, but the docstrings are now used to
generate public API docs.

Author: meshy

src/django_subatomic/db.py

@@ -110,7 +110,6 @@ def savepoint(*, using: str | None = None) -> Generator[None]:
 
     Raises:
         _MissingRequiredTransaction: if we are not in a transaction
-            See Note [_MissingRequiredTransaction in tests]
     """
     with (
         transaction_required(using=using),
@@ -130,8 +129,6 @@ def transaction_required(*, using: str | None = None) -> Generator[None]:
     because we don't want to run the risk of allowing code to pass tests
     but fail in production.
 
-    See Note [_MissingRequiredTransaction in tests]
-
     Raises:
         _MissingRequiredTransaction: if we are not in a transaction.
     """

src/django_subatomic/test.py

@@ -31,8 +31,6 @@ def part_of_a_transaction(using: str | None = None) -> Generator[None]:
 
     Note that this does not handle after-commit callback simulation. If you need that,
     use [`transaction`][django_subatomic.db.transaction] instead.
-
-    See Note [_MissingRequiredTransaction in tests]
     """
     with transaction.atomic(using=using):
         yield