Revert sample code changes as requested by @tarekgh

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