ms-vscode.csharp to ms-dotnettools.csharp by devlead · Pull Request #1424 · PowerShell/PSScriptAnalyzer

C# extension has changed its name from "ms-vscode.csharp" to "ms-dotnettools.csharp", this means all extensions depending on it needs to be updated and i.e. all repositories with extension.json containing

"recommendations": [
    "ms-vscode.csharp"
 ]

or you get errors like