Derive Debug on FileType.

Partially fixes #32054

src/libstd/fs.rs

@@ -141,7 +141,7 @@ pub struct File {
 
 /// An structure representing a type of file with accessors for each file type.
 #[stable(feature = "file_type", since = "1.1.0")]
-#[derive(Copy, Clone, PartialEq, Eq, Hash)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub struct FileType(fs_imp::FileType);
 
 /// A builder used to create directories in various manners.

src/libstd/sys/unix/fs.rs

@@ -84,7 +84,7 @@ pub struct OpenOptions {
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct FilePermissions { mode: mode_t }
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub struct FileType { mode: mode_t }
 
 pub struct DirBuilder { mode: mode_t }

src/libstd/sys/windows/fs.rs

@@ -38,7 +38,7 @@ pub struct FileAttr {
     reparse_tag: c::DWORD,
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, Hash)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub enum FileType {
     Dir, File, SymlinkFile, SymlinkDir, ReparsePoint, MountPoint,
 }