Add IdnMapping.GetAscii and currency symbol behavioral difference examples to ICU globalization breaking change

docs/core/compatibility/globalization/5.0/icu-globalization-api.md

@@ -1,7 +1,8 @@
 ---
 title: "Breaking change: Globalization APIs use ICU libraries on Windows 10"
 description: Learn about the globalization breaking change in .NET 5 where ICU libraries are used for globalization functionality instead of NLS on Windows 10.
-ms.date: 02/15/2022
+ms.date: 03/10/2026
+ai-usage: ai-assisted
 ---
 # Globalization APIs use ICU libraries on Windows 10
 
@@ -52,6 +53,21 @@ string text = string.Format("{0:C}", 100);
 - In .NET Core 3.1 and earlier versions on Windows, the value of text is `"100,00 €"`.
 - In .NET 5 and later versions on Windows 19H1 and later versions, the value of text is `"100,00 ¤"`, which uses the international currency symbol instead of the euro. In ICU, the design is that a currency is a property of a country or region, not a language.
 
+### IdnMapping.GetAscii
+
+Consider the following code that calls <xref:System.Globalization.IdnMapping.GetAscii(System.String)?displayProperty=nameWithType> to convert an internationalized domain name label to its ASCII-compatible encoding.
+
+```csharp
+var mapping = new System.Globalization.IdnMapping();
+string asciiName = mapping.GetAscii("ABCDEFG");
+Console.WriteLine(asciiName);
+```
+
+- In .NET Core 3.1 and earlier versions on Windows, the snippet prints `ABCDEFG`.
+- In .NET 5 and later versions on Windows 10 May 2019 Update and later versions, the snippet prints `abcdefg`.
+
+ICU lowercases domain name labels as part of the ASCII-compatible encoding process. NLS doesn't lowercase labels that contain no international characters, so the original casing is preserved.
+
 ### Day-of-week abbreviations
 
 The <xref:System.Globalization.DateTimeFormatInfo.GetShortestDayName(System.DayOfWeek)?displayProperty=nameWithType> method obtains the shortest abbreviated day name for a specified day of the week.