extensions/typescript-language-features/src/languageFeatures/diagnostics.ts/DiagnosticsManager/deleteDiagnostic
class DiagnosticsManager:	public deleteDiagnostic(resource: vscode.Uri, diagnostic: vscode.Diagnostic): void {
		const fileDiagnostics = this._diagnostics.get(resource);
		if (fileDiagnostics) {
			fileDiagnostics.delete(diagnostic);
			this.rebuildFile(fileDiagnostics);
		}
	}