Update ShortestDayNames example output to match current runtime behavior

Co-authored-by: tarekgh <10833894+tarekgh@users.noreply.github.com>

Author: Copilot

snippets/csharp/System.Globalization/DateTimeFormatInfo/GetShortestDayName/dtfi1.cs

@@ -103,16 +103,16 @@ This code example uses the en-US culture.
         ""
 
         ShortestDayNames...
-        "S"
-        "M"
-        "T"
-        "W"
-        "T"
-        "F"
-        "S"
+        "Su"
+        "Mo"
+        "Tu"
+        "We"
+        "Th"
+        "Fr"
+        "Sa"
 
         GetShortestDayName(DayOfWeek.Sunday)...
-        "S"
+        "Su"
 
         Initial DateTime format patterns for the 'd' format specifier...
         "M/d/yyyy"

snippets/visualbasic/System.Globalization/DateTimeFormatInfo/GetShortestDayName/dtfi1.vb

@@ -97,16 +97,16 @@ Class Sample
         '""
         '
         'ShortestDayNames...
-        '"S"
-        '"M"
-        '"T"
-        '"W"
-        '"T"
-        '"F"
-        '"S"
+        '"Su"
+        '"Mo"
+        '"Tu"
+        '"We"
+        '"Th"
+        '"Fr"
+        '"Sa"
         '
         'GetShortestDayName(DayOfWeek.Sunday)...
-        '"S"
+        '"Su"
         '
         'Initial DateTime format patterns for the 'd' format specifier...
         '"M/d/yyyy"