In VS Code, it is quite handy to use JSDoc comments when writing JavaScript code, as VS Code then provides really helpful intellisense:

I want to implement something similar for my VS Code extension, but have so far failed to understand how this is done. To provide helpful intellisense for my language extension, I have written a bunch of scripts that parse header comments above each function (during the extension build), and add the filtered data to a JSON file. Then, I use this JSON data to provide intellisense (hover tips, autocomplete, etc.).
However, this solution is not dynamic, in the sense that it does not allow the user to provide their own intellisense content by adding these header comments. The extension would have to be rebuilt for this to happen.
So, how can I implement this JSDoc-like commenting feature for my language extension?