Move FileError to a separate file

cache/src/main/scala/coursier/Cache.scala

@@ -802,35 +802,3 @@ object Cache {
   }
 
 }
-
-sealed abstract class FileError(val message: String) extends Product with Serializable
-
-object FileError {
-
-  final case class DownloadError(reason: String) extends FileError(s"Download error: $reason")
-
-  final case class NotFound(file: String, permanent: Option[Boolean] = None) extends FileError(s"Not found: $file")
-
-  final case class ChecksumNotFound(
-    sumType: String,
-    file: String
-  ) extends FileError(s"$sumType checksum not found: $file")
-
-  final case class ChecksumFormatError(
-    sumType: String,
-    file: String
-  ) extends FileError(s"Unrecognized $sumType checksum format in $file")
-
-  final case class WrongChecksum(
-    sumType: String,
-    got: String,
-    expected: String,
-    file: String,
-    sumFile: String
-  ) extends FileError(s"$sumType checksum validation failed: $file")
-
-  sealed abstract class Recoverable(message: String) extends FileError(message)
-  final case class Locked(file: File) extends Recoverable(s"Locked: $file")
-  final case class ConcurrentDownload(url: String) extends Recoverable(s"Concurrent download: $url")
-
-}

cache/src/main/scala/coursier/FileError.scala

@@ -0,0 +1,38 @@
+package coursier
+
+import java.io.File
+
+sealed abstract class FileError(val message: String) extends Product with Serializable
+
+object FileError {
+
+  final case class DownloadError(reason: String) extends FileError(s"Download error: $reason")
+
+  final case class NotFound(
+    file: String,
+    permanent: Option[Boolean] = None
+  ) extends FileError(s"Not found: $file")
+
+  final case class ChecksumNotFound(
+    sumType: String,
+    file: String
+  ) extends FileError(s"$sumType checksum not found: $file")
+
+  final case class ChecksumFormatError(
+    sumType: String,
+    file: String
+  ) extends FileError(s"Unrecognized $sumType checksum format in $file")
+
+  final case class WrongChecksum(
+    sumType: String,
+    got: String,
+    expected: String,
+    file: String,
+    sumFile: String
+  ) extends FileError(s"$sumType checksum validation failed: $file")
+
+  sealed abstract class Recoverable(message: String) extends FileError(message)
+  final case class Locked(file: File) extends Recoverable(s"Locked: $file")
+  final case class ConcurrentDownload(url: String) extends Recoverable(s"Concurrent download: $url")
+
+}