Returns the sentences from a certain block.

@param {string} block The HTML inside a HTML block.
@returns {Array<string>} The list of sentences in the block.
function getSentencesFromBlock( block ) {
	const sentenceTokenizer = new SentenceTokenizer();
	const { tokenizer, tokens } = sentenceTokenizer.createTokenizer();
	sentenceTokenizer.tokenize( tokenizer, block );

	return tokens.length === 0 ? [] : sentenceTokenizer.getSentencesFromTokens( tokens );
}