Fix string highlighting when escaping quote marks in string literals

[Rekkonnect]

According to this article, quote marks are escaped in a variety of ways.

Here are some examples coming from the aforementioned article:

'Mike\'s House'
"Mike's House"
'Mike''s House'

From the above examples, only the double single-quote character escaping works in SQL CE:

'Mike''s House'

The other two queries are invalid and cause parsing errors. Supporting only this case is sufficient.