Add to FAQ how to rename the output of a workflow using input

It would be good to add how to rename using the input name with `#{}`.

https://github.com/galaxyproject/training-material/blob/29515801ffdb2d5874abe3ecafc5253b4bfe4134/faqs/galaxy/workflows_rename_output.md?plain=1#L12

Open faqs/galaxy/workflows_rename_output.md at the linked line and review the existing FAQ guidance. Add an explanation of how to rename workflow output using the input name with `#{}`; it is done when that usage is clearly documented in the FAQ.

Written by the indexing model from the issue text.