"cs" isn't recognized as a syntax highlighting identifier for "C#"

[pvginkel]

Description

"cs" isn't recognized as an alias for C# syntax highlighting. "csharp" is.

• Can you reproduce the issue?

Steps to reproduce

Create a markdown document like this:

```cs
int x;
```

E.g. GitHub and Typora recognize this.

Expected behavior:

Code blocks with the "cs" identifier render as C# code.

Actual behavior:

Code blocks with the "cs" identifier are not syntax highlighted.

Versions

• Mark Text version: v0.16.3
• Operating system: Windows 10