Grab the #htmx web-types from the repo to get auto-completion and docs.
Web-types: https://github.com/bigskysoftware/htmx/blob/master/editors/jetbrains/htmx.web-types.json
How to use it: https://github.com/JetBrains/web-types#web-types
Original source: X (ex-Twitter)
Additional link: Maximizing Productivity: PyCharm and htmx Integration