code: function getRelevantWords( text, locale ) {
  	if ( ! isEqual( text, previousRelevantWords.text ) || ! isEqual( locale, previousRelevantWords.locale ) ) {
  		previousRelevantWords = {
  			text,
  			locale,
  			data: calculateRelevantWords( text, locale ),
  		};
  	}
  	return previousRelevantWords.data;
  }
docs: Retrieve the relevant words. Uses cached version when possible.
  
  @param {string} text   The text.
  @param {string} locale The locale.
  
  @returns {Object} The relevant words.