I've just updated the BBEdit - FileMaker Clippings repository created by rjkantor on GitHub.
The clippings have been updated to include all functions up to v20. They are arranged by group, for ease of access.
There is also a language file, to ensure all the FileMaker functions are properly highlighted.
I've only just pushed the changes up to my own fork, so I'll link to that.
Ensure that you get the fmp20 branch
BBEdit is one of the best text editors for MacOS. Though its free to download and use forever, the Pro features will stop after 30 days. It is well worth the value of paying for the extra features.