[Bug]: Diagnostics are executed for non-C# files when no default formatter is configured

[rvnlord]

Environment:

• Windows 10
• CSharpier: v10.0.3

Summary

DiagnosticsService.runDiagnostics() incorrectly assumes that CSharpier should handle a file when editor.defaultFormatter is null:

let a = workspace.getConfiguration("editor", uri).get("defaultFormatter");
let i = ... && (a == null || a === "csharpier.csharpier-vscode");

When opening a .d.ts file (typescript language ID), no default formatter may be configured for TypeScript, causing a == null to evaluate to true. As a result, CSharpier treats the file as if it should be formatted, even though it isn't a supported language.

Additionally, registerEditorEvents() invokes diagnostics on onDidChangeActiveTextEditor and onDidSaveTextDocument without checking the document's language ID.

Workarounds

Configure explicit formatters for TS/JS files:

"[typescript]": {
    "editor.defaultFormatter": "vscode.typescript-language-features"
},
"[typescriptreact]": {
    "editor.defaultFormatter": "vscode.typescript-language-features"
},
"[javascript]": {
    "editor.defaultFormatter": "vscode.typescript-language-features"
},
"[javascriptreact]": {
    "editor.defaultFormatter": "vscode.typescript-language-features"
}

Or disable diagnostics entirely:

"csharpier.enableDiagnostics": false

Expected Behavior

Diagnostics should only run for languages supported by CSharpier (C# and XML), regardless of whether editor.defaultFormatter is configured.

Actual Behavior

Opening or saving unsupported files such as .d.ts can trigger CSharpier diagnostics if no language-specific formatter has been configured.