Update derive attibute span to start after opening '('

Update derive attibute span to start after opening '('

Fixes 4984

When parsing derive attributes we're only concerned about the traits
and comments listed between the opening and closing parentheses.

Derive attribute spans currently start at the '#'.

    Span starts here
    |
    v
    #[derive(...)]

After this update the derive spans start after the opening '('.

    Span starts here
             |
             V
    #[derive(...)]