JSdoc in htmx.js + generated TypeScript definition

[Telroshan]

Highlights

• Added JSDoc basically everywhere
• Used parent types whenever possible (i.e. Node instead of Element, Element instead of HTMLElement and so on)
• Typescript types definition is now generated, using npm run type-declarations
• Inlined public API's functions within the htmx object itself as tsc would otherwise generate invalid TypeScript code
• I put all custom typedefs in the global scope so that tsc properly exports them, and at the bottom of the file as I thought it would be pretty annoying to have to scroll past 150~ lines of JSDoc to start reading the code
• To avoid making too many changes to the code, I added a few // @ts-ignore in places where code is valid but tsc is too strict

Tests pass, also ran the tests in the extensions repo, all clear

Going further

If this is accepted, I would recommend going further with the following:

• Call tsc in the npm t script to have the pipeline check the code is correctly typed before merging PRs
• Make a custom JS script (called with node in the npm command along tsc) to copy the JSDoc descriptions and default values hints (as all JSDoc is lost along tsc's generation)

[1cg]

lgtm