Comment for #9035 (#9040)

Preserve the constraint in code as well as in the commit message for #9035.

Author: rainersigwald

src/MSBuild/LiveLogger/Terminal.cs

@@ -16,7 +16,7 @@ namespace Microsoft.Build.Logging.LiveLogger;
 internal sealed class Terminal : ITerminal
 {
     /// <summary>
-    /// The encoding read from <see cref="Console.OutputEncoding"/> when the terminal is instantiated.
+    /// The encoding read from <see cref="Console.OutputEncoding"/> when the terminal is constructed.
     /// </summary>
     private readonly Encoding _originalOutputEncoding;
 
@@ -67,6 +67,10 @@ public Terminal()
         _originalOutputEncoding = Console.OutputEncoding;
         Console.OutputEncoding = Encoding.UTF8;
 
+        // Capture the TextWriter AFTER setting the encoding, because setting
+        // the encoding creates a new TextWriter in the Console class, but it's
+        // possible to hang on to the old one (with the wrong encoding) and emit
+        // garbage, as in https://github.com/dotnet/msbuild/issues/9030.
         Output = Console.Out;
     }