Redo printing to stderr to avoid:

warning: extension declares a conformance of imported type 'FileHandle' to imported protocol 'TextOutputStream'; this will not behave correctly if the owners of 'Foundation' introduce this conformance in the future

Partial #696

Signed-off-by: Ross Goldberg <484615+rgoldberg@users.noreply.github.com>

Sources/mas/Formatters/Utilities.swift

@@ -13,15 +13,21 @@ import Foundation
 /// Terminal Control Sequence Indicator.
 private let csi = "\u{001B}["
 
-private var standardError = FileHandle.standardError
+private var standardError = FileHandleTextOutputStream(FileHandle.standardError)
+
+private struct FileHandleTextOutputStream: TextOutputStream {
+    private let fileHandle: FileHandle
+
+    init(_ fileHandle: FileHandle) {
+        self.fileHandle = fileHandle
+    }
 
-extension FileHandle: TextOutputStream {
     /// Appends the given string to the stream.
-    public func write(_ string: String) {
+    func write(_ string: String) {
         guard let data = string.data(using: .utf8) else {
             return
         }
-        write(data)
+        fileHandle.write(data)
     }
 }