Remove unuused internal function

internal/fsx/open.go

@@ -1,31 +0,0 @@
-package fsx
-
-import "io/fs"
-
-// OpenFS opens the named file in filesystem.
-// If opening the file results in an error, returns [ErrFile].
-func OpenFS(name string, fsys fs.FS) fs.File {
-	file, err := fsys.Open(name)
-	if err != nil {
-		return ErrFile{Err: err}
-	}
-	return file
-}
-
-// ErrFile implements a no-op [fs.File].
-//
-// Every operation will return an underlying error
-type ErrFile struct {
-	Err error
-}
-
-func (err ErrFile) Stat() (fs.FileInfo, error) {
-	return nil, err.Err
-}
-func (err ErrFile) Read([]byte) (int, error) {
-	return 0, err.Err
-}
-
-func (err ErrFile) Close() error {
-	return err.Err
-}