Fixed the link to open Currency Calculator (#787)

index.html

@@ -571,7 +571,7 @@ <h3>solves cubic equations, providing real or complex solutions</h3>
                 <h2>Currency Calculator</h2>
                 <h3>Converts the value of one Currency unit into another Currency unit.</h3>
                 <div class="card-footer">
-                    <a href="./Calculators/Currency-Calculator/Currency-Calculator.html" target="_blank">
+                    <a href="./Calculators/Currency-Calculator/index.html" target="_blank">
                         <button>Try Now</button>
                     </a>
                     <a href="https://github.com/Rakesh9100/CalcDiverse/tree/main/Calculators/Currency-Calculator" title="Source Code" target="_blank">