Remove section about mixing PUSH and POP

[mjfwebb]

This section is not needed as it describes what can be considered normal GraphQL usage.

[neo-technology-commit-status-publisher]

Thanks for the documentation updates.

The preview documentation has now been torn down - reopening this PR will republish it.

[github-actions]

💔 All backports failed

Status	Branch	Result
❌	6.x	Backport failed because of merge conflicts You might need to backport the following PRs to 6.x: - review suggestions - updates to mutation pages - updates for the update mutation page - some nit to pick

Manual backport

To create the backport manually run:

backport --pr 204

Questions ?

Please refer to the Backport tool documentation and see the Github Action logs for details