That sounds weird to me, it's like saying:
// hello }
is an invalid Java comment because it closes a block.

It shouldn't be hard to skip comments ("dash dash ... newline" and "/* ... */" -> boolean inComment), the same way the strings are skipped (inQuote).

To give incentive: it's not just English's contractions, but also makes it impossible to quickly/temporarily comment out lines of code or parts of a line.