Some quick fixes and tidy-up

[nblumhardt]

Always use display formatting at the top level for scalars - it turns out that it seems odd to see a DateTime end up as ISO-8601 in a log message.

ConsoleThemeStyle.Object -> ConsoleThemeStyle.Scalar (obsoleting the old name). This name was carried over from the old literate console sink and isn't representative of what the color means, which is, a scalar-captured value of type other than number, bool or string.

Color JSON based on the underlying capture type to distinguish actual strings from other scalars.

Ugly example, showing the difference between rendering of a top-level DateTime and one embedded within a structure. Also note that only the actual string uses ConsoleThemeStyle.String - the number, rendered as the string "NaN", uses number coloring, and likewise the DateTime "Utc" uses scalar coloring.

In real log data, where most entries are real strings and regular numbers, this isn't so ridiculously colorful ;-)

[nblumhardt]

Tests should be sorted now.

It's tough getting the right balance between predictability and ergonomics. I really put this sink through its paces today debugging some new code in Seq - I think these are the somewhat annoying quirks in the new version, should be super awesome now :-)

[nblumhardt]

Folks, I'm keen to push this one through since a lot of people are just now trying the updated sink for the first time, and will find some of these quirks (particularly the first one - using JSON-style formatting a bit over-zealously) a bit odd. Going to hit the button when these tests pass (if, I suppose ;-))