Update ISC001, ISC002 to check in f-strings

[dhruvmanila]

ISC001 and ISC002 checks for implicitly concatenated strings over a single or multiple lines.

The rules needs to be updated to account for the f-strings. The implementation using ranges to check if 2 consecutive strings are implicitly concatenated.

Proposed solution

1. We'll need to get the f-string range from the Indexer when we encounter a FStringStart token.
2. Another solution would be to consume all of the tokens from FStringStart to FStringEnd to get the range. I think using the Indexer is better.