Add to User Guide about mutually exclusive inputs

[kinow]

From Matrix:

I think possible places for this content would be FAQ, Advanced Topics, or How-Tos. Something short, and that can be linked so users can bookmark, share, and maintainers can reply to users with a link as well. It'd be nice too that if that appeared in the search for different/possible search queries (i.e. searching for things like "mutual input parameters", "mutual exclusive parameters", and similar queries if possible).

[mr-c]

https://common-workflow-languageuser-guide.readthedocs.io/en/latest/topics/inputs.html#inclusive-and-exclusive-inputs should have the content from https://common-workflow-languageuser-guide.readthedocs.io/en/latest/faq.html#how-do-i-describe-dependent-or-exclusive-input-parameters-e-g-how-do-i-use-record-inputs & https://common-workflow-languageuser-guide.readthedocs.io/en/latest/faq.html#how-do-i-set-mutually-exclusive-parameters moved in ; with coherent examples