Issue  6889 & 2456 - Fix diagnostic messages for OnScomeStatement

[Issue 6889](https://issues.dlang.org/show_bug.cgi?id=6889) - "finally" mentioned in a compilation error, instead of "scope(exit)" or "scope(success)"
[Issue 2456](https://issues.dlang.org/show_bug.cgi?id=2456) - "cannot put catch statement inside finally block", missing line number

Points:
- Prevent jumping in and out of `scope(success)` block
- Prevent jumping in and out of `scope(exit)` block
- Prevent jumping in `scope(failure)` block (but jump out of it is allowed)