There are some formatting issues with the arguments (the incorrect blocks and apostrophes). I've yet to go through the whole metrics docs, noting them here as I find them for when I get a chance to fix them or if anyone wants to help!

Incorrect:
https://pytorch-lightning.readthedocs.io/en/latest/metrics.html#f1-func
https://pytorch-lightning.readthedocs.io/en/latest/metrics.html#fbeta-func

Correct examples:
https://pytorch-lightning.readthedocs.io/en/latest/metrics.html#iou-func
(among others)

Related: #4837

Edit:
Also noticed that F1 has an unused beta arg that shouldn't be there (we have fbeta), though that's probably a separate issue.