Imports not described in the documentation

Reading the documentation examples , for example https://arrow-kt.io/learn/typed-errors/working-with-typed-errors/ ,
It is sometimes hard to know for a begginer which import to use.

For example it is needed to add import `arrow.core.right` and `import arrow.core.raise.ensure` to make the examples work.

Start with the typed-errors documentation page linked in the issue and review its examples for imports that are required but not shown. Document the needed imports, including arrow.core.right and arrow.core.raise.ensure, so a beginner can run the examples successfully.

Written by the indexing model from the issue text.