removed string from restriction

include/matador/query/builder.hpp

@@ -64,9 +64,9 @@ using Boolean = typed_data_type<bool>;
 using Varchar = sized_typed_data_type<std::string>;
 using Blob = sized_typed_data_type<std::vector<std::byte>>;
 
-class restriction {
+class constraint {
 public:
-    explicit restriction(std::string name)
+    explicit constraint(std::string name)
     : name_(std::move(name)) {}
 
     [[nodiscard]] const std::string& name() const;
@@ -126,7 +126,7 @@ public:
   constraint_builder& references(std::string table, std::string column);
 
   // ReSharper disable once CppNonExplicitConversionOperator
-  operator object::restriction() const; // NOLINT(*-explicit-constructor)
+  operator object::constraint() const; // NOLINT(*-explicit-constructor)
 
 private:
   std::string constraint_name;