RFC: Escaping doc comments inside doc comments

It's useful to users to include code examples in documentation comments. Sometimes you need to illustrate what the output of different code examples are, so you put it in a comment below, and if it's multiple lines, you use a block comment. The problem is that TSDoc doesn't correctly parse this:

/**
 * ```
 * getAverage()
 * /* 'some output' */
 * ```
 */
function getAverage(x, y) {
    return (x + y) / 2.0;
}

I think it should handle block comments when they're inside a code block in the documentation comment.

Reproduce the TypeScript example from the issue with the repository's TSDoc parser; no implementation file or test is named, so first locate the parser entry point and related code-block tests. Done means a block comment inside a fenced code example remains part of that example without terminating or corrupting the surrounding documentation comment.