Hi Christian, et al,

I'm guessing that you're all busy with working towards a 9.1 release (yay!), but if you have time would you consider an incredibly minor PR?

I recently noticed that the BaseX GUI supports completion and it's great. I found a small typo in the completions:
`sliding=for tumbling window` should be
`sliding=for sliding window`

It's super-duper simple, but I have a branch with the typo fixed[1].

In any event, thanks!
Looking forward to the next release.
Best,
Bridger
[1] https://github.com/CanOfBees/basex/tree/fix-completions-typo