Fix default argument

Author: armanbilge

api-reports/2_12.txt

@@ -239,7 +239,7 @@ experimental/Chunk[JT] def value: T
 experimental/Fetch[JO] def fetch(info: RequestInfo, init: RequestInit = null): js.Promise[Response]
 experimental/FileReaderSync[JC] def readAsArrayBuffer(blob: Blob): ArrayBuffer
 experimental/FileReaderSync[JC] def readAsDataURL(blob: Blob): URL
-experimental/FileReaderSync[JC] def readAsText(blob: Blob, encoding: String = "UTF-8"): String
+experimental/FileReaderSync[JC] def readAsText(blob: Blob, encoding: String?): String
 experimental/Fullscreen[SO] def exitFullscreen(): js.UndefOr[js.Promise[Unit]]
 experimental/Fullscreen[SO] def fullscreenElement: Element
 experimental/Fullscreen[SO] def fullscreenEnabled: Boolean

api-reports/2_13.txt

@@ -239,7 +239,7 @@ experimental/Chunk[JT] def value: T
 experimental/Fetch[JO] def fetch(info: RequestInfo, init: RequestInit = null): js.Promise[Response]
 experimental/FileReaderSync[JC] def readAsArrayBuffer(blob: Blob): ArrayBuffer
 experimental/FileReaderSync[JC] def readAsDataURL(blob: Blob): URL
-experimental/FileReaderSync[JC] def readAsText(blob: Blob, encoding: String = "UTF-8"): String
+experimental/FileReaderSync[JC] def readAsText(blob: Blob, encoding: String?): String
 experimental/Fullscreen[SO] def exitFullscreen(): js.UndefOr[js.Promise[Unit]]
 experimental/Fullscreen[SO] def fullscreenElement: Element
 experimental/Fullscreen[SO] def fullscreenEnabled: Boolean

src/main/scala/org/scalajs/dom/experimental/FileReaderSync.scala

@@ -44,5 +44,5 @@ class FileReaderSync() extends js.Object {
    *
    * MDN
    */
-  def readAsText(blob: Blob, encoding: String = "UTF-8"): String = js.native
+  def readAsText(blob: Blob, encoding: String = js.native): String = js.native
 }