Fix codeblock detection to catch blocks not on first lines

[Gerrit0]

This PR fixes #132820

[mjbvz]

Thanks for the PR! I think this makes sense but can you also add some tests to make sure we are doing the correct thing and don't regress this in the future:

vscode/extensions/typescript-language-features/src/test/unit/previewer.test.ts

Line 16 in e4eaed4

suite('typescript.previewer', () => {

[mjbvz]

One thing actually: we need to support @example without fenced code blocks: https://jsdoc.app/tags-example.html

For those cases, the text should be treated as if it was a code block even though there is no explicit fenced code block

[Gerrit0]

@mjbvz am I missing something obvious here? I tried to follow the instructions at https://github.com/microsoft/vscode/blob/main/test/unit/README.md to run the tests (with --grep typescript.previewer since there are entirely too many). This command can't seem to find the tests.
Running with yarn run mocha --ui tdd --run ./extensions/typescript-language-features/src/test/unit/previewer.test.ts can't find the file (it replaces the ts extension with js). If I try to run the built file in a way that I'd expect to work, yarn test .\extensions\typescript-language-features\out\test\unit\previewer.test.js, it can't find vscode

[mjbvz]

You can run them through VS Code's debug view:

[Gerrit0]

Thanks! No wonder I didn't see that... have never really heavily used the debugger for tests.

Test cases:

/**
 * @example
 * foo();
 * 
 * @example
 * Caption
 * ```ts
 * foo();
 * ```
 */
function foo() {

}

/**
 * @example <caption>Caption</caption>
 * bar();
 * 
 * @example <caption>Caption</caption>
 * ```ts
 * bar();
 * ```
 */
function bar() {
    
}

[Gerrit0]

Disabled tests were failing, unrelated to my changes.

[mjbvz]

LGTM besides the comments

[mjbvz]

Thanks! This change will in the next VS Code 1.62 insiders build