src/vs/workbench/services/untitled/common/untitledTextEditorModel.ts/UntitledTextEditorModel/setEncoding
class UntitledTextEditorModel:	async setEncoding(encoding: string): Promise<void> {
		const oldEncoding = this.getEncoding();
		this.preferredEncoding = encoding;

		// Emit if it changed
		if (oldEncoding !== this.preferredEncoding) {
			this._onDidChangeEncoding.fire();
		}
	}