Add syntax highlighting support for jsdoc custom tags

[daprahamian]

If I add a custom jsdoc tag to my project, it would be nice if it would have proper syntax highlighting in my doc comments.

Example:

// my-jsdoc-tag.js
exports.defineTags = function(dictionary) {
  dictionary.defineTag('my-tag', { ... });
};

//my-code.js
/**
 * @param {number} param some input
 * @returns {number} the input + 1
 * @my-tag <-- I want this to be highlighted like @param and @returns are
function foo(param) {
  return param + 1;
}

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Highlight invalid params in doc comments (#69677)
• support destructuring parameter @param tag in tsdoc (#80368)

[mjbvz]

Opened microsoft/TypeScript-TmLanguage#772 to track upstream