Document IDE2000-2006

### Describe the issue or suggestion

See https://github.com/dotnet/roslyn/blob/main/src/Features/RulesMissingDocumentation.md. These rules are for newline preferences.

Also update [here](https://github.com/dotnet/docs/blob/22c15732301a729cd041b10984879d05a9e552cc/docs/fundamentals/code-analysis/style-rules/language-rules.md?plain=1#L211-L217).