Added Ngramsearch Function to Calculate the Non-symmetric Difference Between Needle and Haystack

Why it matters

This feature provides a way to perform approximate string matching by calculating how much a target string (needle) differs from a source string (haystack) based on n-gram comparison. It solves the problem of efficient fuzzy matching and similarity assessment in queries, which is valuable for text search, data cleaning, or identifying close matches within large datasets.

How to use it

Use the ngramSearch function in SQL queries by passing the needle and haystack strings as arguments. For example:

SELECT ngramSearch('needle_string', 'haystack_string')

This will return an integer indicating the non-symmetric difference between the two strings based on their n-grams.