Unify roslyn rule description for rules with shared options

There are two ways to describe rules with shared options:
- Same page - [IDE0007 + IDE0008](https://github.com/dotnet/docs/blob/main/docs/fundamentals/code-analysis/style-rules/ide0007-ide0008.md). Each rule has table with description and then related to both rule option are described.
- Different page - [IDE0210](https://github.com/dotnet/docs/blob/main/docs/fundamentals/code-analysis/style-rules/ide0210.md) + [IDE0211](https://github.com/dotnet/docs/blob/main/docs/fundamentals/code-analysis/style-rules/ide0210.md). Each rule has own page and each page contains option.

What way is right? Maybe need to unify them?

---
#### Document Details

⚠ *Do not edit this section. It is required for learn.microsoft.com ➟ GitHub issue linking.*

* ID: f9e99e36-a3b1-ac38-c66d-905d9be1fa01
* Version Independent ID: d035351b-536b-6f80-69ac-4d12527284c3
* Content: [IDE0007 and IDE0008: 'var' preferences - .NET](https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/style-rules/ide0007-ide0008)
* Content Source: [docs/fundamentals/code-analysis/style-rules/ide0007-ide0008.md](https://github.com/dotnet/docs/blob/main/docs/fundamentals/code-analysis/style-rules/ide0007-ide0008.md)
* Service: **dotnet-fundamentals**
* GitHub Login: @gewarren
* Microsoft Alias: **gewarren**