* allow(clippy::upper_case_acronyms) for rust enum entries that match
SQLite constants.
* allow(clippy::needless_return) for collation_needed_callback until we
find a way to propagate the error.
This just using them in patterns without a catchall. I left things alone
that seem very unlikely to change (`Value`, `ValueRef`, `DatabaseName`,
etc...). This might help reduce the number of breaking changes we need
(rusqlite is still pre-1.0 so it doesn't really matter that much, but
breaking changes complicate the story around when we can cut releases).
Replace `Row::get` by `Row::get_checked`,
And rename original `Row::get` to `Row::get_unwrap`.
`Stmt::query_map`, `Stmt::query_map_named`, `Stmt::query_row`,
`Conn::query_row` and `Conn::query_row_named` callback parameter must return a `Result`.
