Docs: specify applicability of is_retryable (#1218)

Because the server-side state of auto-commit transactions cannot be known by
the driver (they might even be partially committed), it's not safe to retry them
solely based on the exception observed. Business logic is required to determine
if the auto-commit transaction succeeded or failed after observing an error
client-side.

Author: robsdedude

src/neo4j/exceptions.py

@@ -782,6 +782,12 @@ def is_retryable(self) -> bool:
         retry. This method makes mostly sense when implementing a custom
         retry policy in conjunction with :ref:`explicit-transactions-ref`.
 
+        .. warning::
+
+            Auto-commit transactions
+            (:meth:`.Session.run`/:meth:`.AsyncSession.run`) are not retryable
+            regardless of this value.
+
         :returns: :data:`True` if the error is retryable,
             :data:`False` otherwise.
 
@@ -1008,6 +1014,12 @@ def is_retryable(self) -> bool:
         retry. This method makes mostly sense when implementing a custom
         retry policy in conjunction with :ref:`explicit-transactions-ref`.
 
+        .. warning::
+
+            Auto-commit transactions
+            (:meth:`.Session.run`/:meth:`.AsyncSession.run`) are not retryable
+            regardless of this value.
+
         :returns: :data:`True` if the error is retryable,
             :data:`False` otherwise.