Fix pagination example

The example of how to set the response HTTP headers was using the
old method of parsing the cursor and the wrong name for the query
runner class. Fix both issues.

Author: rra

docs/user-guide/database/pagination.rst

@@ -95,9 +95,7 @@ The parameter declaration should generally look something like the following:
            str | None,
            Query(
                title="Pagination cursor",
-               description=(
-                   "Optional cursor used when moving between pages of results"
-               ),
+               description="Cursor to navigate paginated results",
            ),
        ] = None,
        limit: Annotated[
@@ -224,26 +222,38 @@ This is the recommended way to return pagination information alongside a result.
 Here is a very simplified example of a route handler that sets this header:
 
 .. code-block:: python
+   :emphasize-lines: 27-36
 
    @router.get("/query", response_class=Model)
    async def query(
        *,
        cursor: Annotated[
-           ModelCursor | None,
-           Query(),
-           BeforeValidator(lambda c: ModelCursor.from_str(c) if c else None),
+           str | None,
+           Query(
+               title="Pagination cursor",
+               description="Cursor to navigate paginated results",
+           ),
        ] = None,
-       limit: Annotated[int | None, Query()] = None,
-       session: Annotated[
-           async_scoped_session, Depends(db_session_dependency)
-       ],
+       limit: Annotated[
+           int,
+           Query(
+               title="Row limit",
+               description="Maximum number of entries to return",
+               examples=[100],
+               ge=1,
+               le=100,
+           ),
+       ] = 100,
        request: Request,
        response: Response,
    ) -> list[Model]:
-       runner = PydanticQueryRunner(Model, ModelCursor)
+       parsed_cursor = None
+       if cursor:
+           parsed_cursor = ModelCursor.from_str(cursor)
+       runner = PaginatedQueryRunner(Model, ModelCursor)
        stmt = build_query(...)
        results = await runner.query_object(
-           session, stmt, cursor=cursor, limit=limit
+           session, stmt, cursor=parsed_cursor, limit=limit
        )
        if cursor or limit:
            response.headers["Link"] = results.link_header(request.url)