A flag to replace removed syntax with blank space

### 🔍 Search Terms

Blank space
ErasableSyntax
Node.js Strip Types
Type Stripping

### ✅ Viability Checklist

- [x] This wouldn't be a breaking change in existing TypeScript/JavaScript code
- [x] This wouldn't change the runtime behavior of existing JavaScript code
- [x] This could be implemented without emitting different JS based on the types of the expressions
- [x] This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
- [x] This isn't a request to add a new utility type: https://github.com/microsoft/TypeScript/wiki/No-New-Utility-Types
- [x] This feature would agree with the rest of our Design Goals: https://github.com/Microsoft/TypeScript/wiki/TypeScript-Design-Goals

### ⭐ Suggestion

A new flag to replace removed syntax during transpilation with blank space. Similarly to http://github.com/bloomberg/ts-blank-space and https://swc.rs/docs/references/wasm-typescript used in Node.js. This would remove the need of sourcemaps.
It can only be used in conjuction with --erasableSyntaxOnly

### 📃 Motivating Example

Example:
```
const foo: string = "Hello World";
```

becomes:

```
const foo = "Hello World";
```

### 💻 Use Cases

1. What do you want to use this for?
Remove the need of sourcemaps after transpilation.
3. What shortcomings exist with current approaches?
None other than only a subset of syntax defined by an existing flag can be stripped.
4. What workarounds are you using in the meantime?
swc and tsblankspace

この issue ではリポジトリのファイルやテストが指定されていません。まず、既存の --erasableSyntaxOnly オプションをコンパイラ内で追跡し、要求されている空白出力を、引用されている swc と ts-blank-space のアプローチと比較してください。完了条件は、新しい互換性のあるフラグが削除された構文を空白に置き換え、消去可能な構文に限定されることです。

索引モデルが issue の本文から書いたものです。