style(Rest): standardize test file formatting

Apply consistent code formatting across Rest test files including:
- Struct field type formatting (remove trailing colons)
- Inline comment repositioning
- Assertion formatting standardization
- Minor punctuation fix in README.md (em dash to hyphen)

Affected files:
- tests/integration/vscode_compatibility.rs
- tests/unit/codegen_tests.rs
- tests/unit/oxc_compiler.rs
- tests/unit/parser_tests.rs
- tests/unit/transformer_tests.rs
- README.md

These formatting changes align the test code with the project's style conventions.

Author: NikolaRHristov

README.md

@@ -77,7 +77,7 @@ The `Rest` compiler was chosen over the existing esbuild pipeline for three
 reasons that directly affect the VSCode build:
 
 1. **OXC is used by VSCode internally.** This means Rest produces output that
-   matches VSCode's own build pipeline — not an approximation.
+   matches VSCode's own build pipeline - not an approximation.
 2. **`emitDecoratorMetadata` support.** VSCode's codebase relies on decorator
    metadata emission. OXC handles this correctly; esbuild has limited support.
 3. **`useDefineForClassFields = false`.** VSCode requires the legacy class