Fix for issue #858 (disallow incrementing/decrementing the value of enum)

Fix for issue #858. Updated the baselines associated with incrementing and decrementing enum types as well.  

This fix is a pretty simple but would it make more sense to add a new SyntaxKind for EnumAccess? I haven't looked too deeply into this but I just wonder if there are other places where we have to check IndexAccess and PropertyAccess to see if they really are accessing an Enum that a refactor like this would simplify.
As far as I can tell the issue is actually coming from that the fact that in checkPropertyAccess() there is the following assignment:

getNodeLinks(node).resolvedSymbol = prop;

This never happens in checkIndexedAccess() and so the symbol is never found. I'm planning on adding logic into checkIndexedAccess() (assuming the IndexedAccess is on an Enum) to do that. After that, the logic you described previously should work.