getTrailingCommentRanges returns comments at the start of the file

<!-- 🚨 STOP 🚨 𝗦𝗧𝗢𝗣 🚨 𝑺𝑻𝑶𝑷 🚨 Half of all issues filed here are duplicates, answered in the FAQ, or not appropriate for the bug tracker. Even if you think you've found a *bug*, please read the FAQ first, especially the Common "Bugs" That Aren't Bugs section! Please help us by doing the following steps before logging an issue: * Search: https://github.com/Microsoft/TypeScript/search?type=Issues * Read the FAQ: https://github.com/Microsoft/TypeScript/wiki/FAQ Please fill in the *entire* template below. --> <!-- Please try to reproduce the issue with `typescript@next`. It may have already been fixed. --> **TypeScript Version:** master **Code:** ```ts // one // two ``` **Expected behavior:** `ts.getTrailingCommentRanges(text, 0)` doesn't return a comment. Both comments are parsed by `ts.getLeadingCommentRanges(text, 0)`. **Actual behavior:** `ts.getTrailingCommentRanges(text, 0)` parses `// one` as a trailing comment. `ts.getLeadingCommentRanges(text, 0)` parses both comments. The special handling of position 0 should also affect trailing comments. With the current behavior I have to remember to not parse trailing comment ranges at position 0 to avoid duplicates. **Related Issues:** This was part of https://github.com/Microsoft/TypeScript/pull/28489 where I first proposed changing this behavior. /cc @rbuckton