Update column-formatting.md (SharePoint#2328)

Author: ldemaris

docs/declarative-customization/column-formatting.md

@@ -188,6 +188,8 @@ This example colors the current field red when the value inside an item's DueDat
 
 To compare the value of a date/time field against a date that's not `@now`, follow the pattern in the following example. The following example colors the current field red if the due date was <= tomorrow. This is accomplished using date math. You can add milliseconds to any date and the result will be a new date. For example, to add a day to a date, you'd add (24\*60\*60\*1000 = 86,400,000). 
 
+This example demonstrates an alternate syntax to express a conditional expression, using the ternary (`?`) operator inside an abstract syntax tree.
+
 ```JSON
 {
    "elmType": "div",