Add missing nodiscard attributes to section pair classes

include/ls-std/io/section-pair/SectionPairIdentifierValidator.hpp

@@ -25,7 +25,7 @@ namespace ls::std::io
       explicit SectionPairIdentifierValidator(ls::std::io::section_pair_identifier _identifier);
       ~SectionPairIdentifierValidator() override;
 
-      bool isValid() override;
+      [[nodiscard]] bool isValid() override;
 
     private:
 

include/ls-std/io/section-pair/SectionPairRowValueValidator.hpp

@@ -25,7 +25,7 @@ namespace ls::std::io
       explicit SectionPairRowValueValidator(ls::std::io::section_pair_row_value _value);
       ~SectionPairRowValueValidator() override;
 
-      bool isValid() override;
+      [[nodiscard]] bool isValid() override;
 
     private: