How to reproduce:
1. Open the attached “My Projectaasdasd.zip“
2. Create a new C# Script (Right click > Create > C# Script)
3. Name the Script “1”

Expected result: No errors are thrown in the Console window
Actual result: Multiple "Identifier expected", "{ expected" and "} expected" errors are thrown in the Console window

Reproducible with: 2020.3.46f1, 2021.3.23f1, 2022.2.13f1, 2023.1.0b10, 2023.2.0a8

Reproduced in: macOS Monterey 12.6

Note: Issue is not reproducible when creating a script without naming it by a number and then renaming the script to a number