Filters word combinations beginning and ending with certain function words.

@param {WordCombination[]} wordCombinations The word combinations to filter.
@param {Array} functionWords The list of function words.
@returns {WordCombination[]} Filtered word combinations.
function filterFunctionWordsAtBeginningAndEnding( wordCombinations, functionWords ) {
	wordCombinations = filterFunctionWordsAtBeginning( wordCombinations, functionWords );
	wordCombinations = filterFunctionWordsAtEnding( wordCombinations, functionWords );
	return wordCombinations;
}