Improve docs

[soininen]

Try making the distinction between entity_byname and element_name_list clearer.

Also add the missing tutorial section about restoring items.

Fixes #411

Checklist before merging

• [x] Documentation (also in Toolbox repo) is up-to-date
• [x] Release notes have been updated
• [x] Unit tests have been added/updated accordingly
• [x] Code has been formatted by black
• [x] Unit tests pass

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 78.23%. Comparing base (75b3b70) to head (a624543).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #412 +/- ## ======================================= Coverage 78.23% 78.23% ======================================= Files 72 72 Lines 9515 9515 Branches 2031 2031 ======================================= Hits 7444 7444 Misses 1735 1735 Partials 336 336 ```

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