Review impact of indices and ranges on existing rules

[sharwell]

https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-8#indices-and-ranges

[sharwell]

This feature includes two syntax changes:

• The ^ operator, which should behave like other prefix operators
• The .. operator
  • a..b: Should behave like a member access operator (no space before or after if on one line, but allow a line break before ..)
  • a..: Should behave like a suffix operator (no space before ..)
  • ..b: Should behave like a prefix operator (no space after ..)
  • ..: Should behave like an identifier