refactor: Refactor import statements and add error handling to check directory existence

- Remove unused import statement for "golang.org/x/exp/slices"
- Add necessary import statement for "golang.org/x/exp/slices"
- Implement error handling code to check directory existence

file.go

@@ -4,11 +4,12 @@
 package configuration
 
 import (
-	"golang.org/x/exp/slices"
 	"io/fs"
 	"os"
 	"path"
 	"path/filepath"
+
+	"golang.org/x/exp/slices"
 )
 
 type files struct {
@@ -137,10 +138,12 @@ func (s *Settings[C]) sanitizeDirectories() {
 			visited[d] = true
 		}
 
-		if _, err := os.Stat(d); os.IsNotExist(err) {
-			s.errors = append(s.errors, newPathDoesNotExistError(d))
 	}
 
+	// check last entry
+	d := s.files.directories[len(s.files.directories)-1]
+	if _, err := os.Stat(d); os.IsNotExist(err) {
+		s.errors = append(s.errors, newPathDoesNotExistError(d))
 	}
 
 }