src/vs/workbench/services/textfile/common/textFileEditorModel.ts/TextFileEditorModel/updatePreferredEncoding
class TextFileEditorModel:	updatePreferredEncoding(encoding: string | undefined): void {
		if (!this.isNewEncoding(encoding)) {
			return;
		}

		this.preferredEncoding = encoding;

		// Emit
		this._onDidChangeEncoding.fire();
	}