fix(curriculum): correct CSS specificity lesson example to use ID selector (#64493)

curriculum/challenges/english/blocks/lecture-css-specificity-the-cascade-algorithm-and-inheritance/672aa62178d5ff57fe4f98e0.md

@@ -192,13 +192,13 @@ The specificity value for internal styles is determined by the selectors used. F
 ```html
 <head>
   <style>
-    .text {
+    #text {
       color: blue;
     }
   </style>
 </head>
 <body>
-  <div class="text">This text is blue.</div>
+  <div id="text">This text is blue.</div>
 </body>
 ```