Update printing docs to include new warning

docs/src/explanations/printing.md

@@ -31,6 +31,12 @@ val myUInt = 33.U
 printf("my normal string" + cf"myUInt = $myUInt")
 ```
 
+Also note that the Scala s-interpolator is deprecated and will output the warning:
+
+```scala mdoc:compile-only
+"s-interpolators for Chisel assert, assume and printf statements are deprecated (since 3.5); use p or cf interpolators instead"
+```
+
 #### Simple formatting
 
 Other formats are available as follows: