LWS-264: Lxlquery grammar and highlighting

[jesperengstrom]

Description

Tickets involved

LWS-264

Summary of changes

• Add rudimentary language rules to the grammar file
• Add tests for the grammar
• Parse the language with custom lezer Tags for certain nodes
• Add codemirror extension that adds CSS classes when encountering those tags
• Add a css file to style those classes, achieving syntax highlighting

try some searches from the help page:
pippi långstrump språk:(engelska OR franska) ÅR>2002]
språk:svenska ÅR>2010 ÅR<=2024 ämne:"sao:Drakar"
träd* bibliografi:"sigel:DST" NOT typ:Text

Or a 'special' qualifier
includeEplikt

Notes:

• The (somewhat) straighforward way of highlighting using nodes -> tags -> classes/styles seems to be the cheapest (compared to iterating through the syntax tree adding decorators - even though we'll be doing that later on) but is limited in that it does not produce nested structures, only an inline element for the most specific exported node in a given place. On the other hand, I don't know if we want/need highlighting at all. But for now I think it's nice for evaluating/debugging purposes. The styling itself is not carefully done :)

• The highlighter extension now belongs to lxlweb. Since it's language specific, it doesn't belong to supersearch and is not a core part of the language either. It imports stuff from codemirror/lezer that lxlweb does not directly depend on, don't know if that's a problem?

(Another solution could be to let the language package export the Highlighter, import it in lxlweb and pass it as a special prop (how many can we handle?) to supersearch that then turns it into an extension.)

[johanbissemattsson]

Really awesome work! 🌟 🙌 I think it would be good to go through the grammar together with the rest of the team (can be done after the PR is merged; we can then also discuss the possible use of brackets to separate the qualifiers) but I think it looks really good in it's current state!