C# highlighting is not respecting the @ symbol in front of a parameter.

Information:

• Prism version: "1.27.0",
• Plugins: none
• Environment: [e.g. Browser, Node, Webpack]

Description
There seems to be a glitch, regarding C# syntax highlighting, not respecting @ symbol before a parameter.

To illustrate, when using the following markdown,

public TChild FirstOfTypeOrDefault(TChild @default = null);

Unexpectedly, 'default' gets highlighted in blue as if it's a keyword.

On the contrary, in this context, '@default' should be treated as a regular parameter and highlighted in black, as '@default' is not a keyword. Therefore, 'default' being highlighted in blue is incorrect.

The expected correct highlighting would treat 'default' as an identifier rather than a keyword, so it should be highlighted in black (or the color assigned for identifiers in your theme) instead of the blue color usually reserved for keywords. This is due to the @ symbol preceding it, which, in C#, effectively makes 'default' a valid identifier instead of a keyword.

Example

public TChild FirstOfTypeOrDefault(TChild @default = null);

Run the supplied C# snippet through Prism's C# grammar and inspect how the @ symbol and default are classified. Done means @default is highlighted as an identifier rather than as the default keyword; no specific file or test is named in the issue.