Formatting fails for entire file when a line contains only whitespace between two comments

@DanielRosenwasser 已经在做这个了。

开始于 2026年4月27日。

• #3630 来自 @copilot-swe-agent —— 已关闭，未合并

Per Ryan's suggestion [here](https://github.com/microsoft/TypeScript/issues/63442) I am reposting this. This bug still occurs in typescript-go version 0.20260427.1
### 💻 Code
```ts
const x = "wont format"
//

//
```
- Notice the white space in line 3 between the two comments
- Attempt to format (in VS code by shift + alt + F)
- Notice how line 1 will not indent, this affects the entire file

This bug is difficult to reproduce if you have the "files.trimTrailingWhitespace" option enabled, as it will remove the whitespace in line 3 on save allowing formatting to work again as intended

This affects both TypeScript and JavaScript files

### 🕗 Version & Regression Information

- This changed between versions 4.5.5 and 6.0.3 (incl dev.20260416 nightly) incl (tsgo 0.20260427.1)
- This is the behavior in every version I tried, and I reviewed the FAQ for entries about formatting and indentation

### ⏯ Playground Link

https://www.typescriptlang.org/play/?ts=6.0.3#code/AQYw9gdgzgLsAewC8wBEB3ScBmYBOAtgIYyoBQA9BWcJRUA
### 🙁 Actual behavior

The formatting for the entire file fails silently. No lines are formatted or indented.

### 🙂 Expected behavior

The formatter should indent code correctly (const x in line 1)

### Additional information about the issue

Issue does not affect /* */ only // comments