fix: twoslash @link comments skipped when multiple appear consecutively

[tsushanth]

Problem

In rehypeSyntaxHighlighting.ts, the loop that strips // @link comment lines from twoslash code blocks mutates the array while iterating over it with .entries():

for (const [i, line] of splitCode.entries()) {
  const parsedLineComment = parseLineComment(line);
  if (!parsedLineComment) continue;
  linkMap.set(word, href);
  splitCode.splice(i, 1);  // shifts all subsequent elements down
}

After splice(i, 1), the element that was at index i+1 shifts to i, but the iterator advances to i+1 on the next tick — skipping it. The result: when two or more consecutive lines are // @link comments, every second one is silently dropped. The skipped line stays in the rendered code output as a visible comment and its link is never added to linkMap, so the hover popup won't contain a link for that token.

Example that triggers the bug — the second @link is silently ignored:

// @link Promise https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise
// @link fetch https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API
const result: Promise<Response> = fetch('/api/data')

Fix

Replace the mutate-in-place loop with a single filter pass that collects links and strips comment lines in one traversal, avoiding the off-by-one from in-place removal.