feat(prql): add prql support

[matthias-Q]

Adds support for PRQL languange.

I hope I added everything thats necessary to add language support.

Closes #6050

[matthias-Q]

Sorry, I have not run cargo xtasks docgen I will do that and update the PR

[EDIT] I had modified that md file by hand. Only difference is, that prql should be a few lines lower. Should push these changes?

[erasin]

The only difference is that prql should be a few lines lower. should these changes be pushed?

Since book/src/generated is an automatically generated file, use cargo xtasks docgen to handle it to avoid conflicts.

I think a normal commit will do the trick.

Alternatively Git provides some rebase and commit merge methods, so you can use git commit --amend to merge some changes directly into the last commit, and then push with --force to overwrite remote branch.

[the-mikedavis]

Otherwise this looks good

(Also see #4892 which talks about separating the highlights for function definitions and references)

[the-mikedavis]

Thanks!