src/vs/editor/contrib/suggest/browser/suggestMemory.ts/PrefixMemory/memorize
class PrefixMemory:	memorize(model: ITextModel, pos: IPosition, item: CompletionItem): void {
		const { word } = model.getWordUntilPosition(pos);
		const key = `${model.getLanguageId()}/${word}`;
		this._trie.set(key, {
			type: item.completion.kind,
			insertText: item.completion.insertText,
			touch: this._seq++
		});
	}