Extracting Workflows from Histories

Overall the tutorial can be followed in 21.01 without issues. Here are a few tiny inconsistencies discovered during the 21.01 release testing phase.

- Point 5 of the [Pretreatments section](https://training.galaxyproject.org/training-material/topics/galaxy-interface/tutorials/history-to-workflow/tutorial.html#pretreatments) mentions a history that can be imported if you don't have any, but it is not clear which is `the one` referenced in the section.
> A Galaxy history from an analysis that you have already run. If you don’t have one handy, you can use this history on usegalaxy.org. Click Import History to bring that history into your workspace on usegalaxy.org. Any history will work with this tutorial, but that’s the one used in the examples.

- Point 4 of the [Set your current history section](https://training.galaxyproject.org/training-material/topics/galaxy-interface/tutorials/history-to-workflow/tutorial.html#set-your-current-history) mentions a `Done` button that does not seem to be there anymore.
> Click the Done button at the top upper left of your histories view.

- The screenshots are a bit outdated and the new icons and small changes in the UI do not match some of the descriptions.

Open the linked history-to-workflow tutorial and review the Pretreatments and Set your current history sections first. Clarify which example history is referenced, verify whether the Done button still exists, and compare the screenshots with the current Galaxy interface. Done means the instructions and screenshots match the current workflow and UI.

Written by the indexing model from the issue text.