Grommet: Use JSDoc instead of TypeScript for strong typing

[brodybits]

In short, I think this could help avoid adding another barrier of entry for external contributors and some other disadvantages discussed in: https://medium.com/javascript-scene/the-typescript-tax-132ff4cb175b

Here is some documentation of using JSDoc comments to add the strong typing to the existing JavaScript, as documented in the following resources:

• https://medium.com/@trukrs/type-safe-javascript-with-jsdoc-7a2a63209b76 - from September 2018, with a big thanks to @rbiggs
• https://devblogs.microsoft.com/typescript/how-to-upgrade-to-typescript-without-anybody-noticing-part-1/
• https://devblogs.microsoft.com/typescript/how-to-upgrade-to-typescript-without-anybody-noticing-part-2/

see also this discussion: prettier/prettier#6286

There should also be a way to use JSDoc comments to completely bypass using *.d.ts, not working 100% due to microsoft/TypeScript#33136

I would like to give this idea sometime in the near future (no promises right now, unfortunately).

++ /cc @rbiggs

[ShimiSun]

Thank you for sharing buddy!! 🚀

[brodybits]

Thanks @ShimiSun for all of your words of encouragement.

I guess my comments in #3271 were too controversial. My opinion remains the same, will do my best to work with whatever decision is taken in the end.