[3.11] Docs: align the param spec of sqlite3.Connection methods with the implementation (GH-108285) (#108288)

- no parameters of create_aggregate() are positional-only
- all parameters of create_collation() are positional-only
(cherry picked from commit 893215a4e7f59eabb8ccdf188c4b9b1de5bd8966)

Co-authored-by: Erlend E. Aasland <erlend@python.org>