Improved code by updating any interfaces

Change-Id: I9a2e630c37f3c427569f5bbd773978c2705dc08c
diff --git a/validation/validator.go b/validation/validator.go
index 343e820..22fcc70 100644
--- a/validation/validator.go
+++ b/validation/validator.go
@@ -6,6 +6,8 @@
 	"regexp"
 	"strings"
 
+	"slices"
+
 	"github.com/korap/korap-mcp/service"
 	"github.com/rs/zerolog"
 )
@@ -101,7 +103,7 @@
 	}
 
 	// Validate query language if provided
-	if req.QueryLanguage != "" && !contains(validQueryLanguages, req.QueryLanguage) {
+	if req.QueryLanguage != "" && !slices.Contains(validQueryLanguages, req.QueryLanguage) {
 		errors = append(errors, ValidationError{
 			Field:   "query_language",
 			Value:   req.QueryLanguage,
@@ -452,13 +454,3 @@
 
 	return sanitized
 }
-
-// contains checks if a string slice contains a specific value
-func contains(slice []string, item string) bool {
-	for _, s := range slice {
-		if s == item {
-			return true
-		}
-	}
-	return false
-}