Fix blog post links

Add .html extension

Author: helenclx

blog/feed.xml

@@ -9,7 +9,7 @@
     <item>
       <title>cbpickaxe and My First (Merged) Pull Request in Python</title>
       <pubDate>Mon, 13 Nov 2023 17:30:14 +0800</pubDate>
-      <link>https://helenclx.github.io/blog/posts/2023-11-13-My-First-PR-in-Python</link>
+      <link>https://helenclx.github.io/blog/posts/2023-11-13-My-First-PR-in-Python.html</link>
       <author>Helen Chong</author>
       <description><![CDATA[About my first pull request in Python that got approved and merged.]]></description>
     </item>

index.html

@@ -136,21 +136,21 @@ <h2 class="section__title">Blog</h2>
                 <h3 class="blog__latest">Latest Blog Posts:</h3>
                 <div class="blog__feed">
                     <div class="blog__entry">
-                        <a href="https://helenclx.github.io/blog/posts/2023-11-13-My-First-PR-in-Python" target="blank">
+                        <a href="https://helenclx.github.io/blog/posts/2023-11-13-My-First-PR-in-Python.html" target="blank">
                             <h4>cbpickaxe and My First (Merged) Pull Request in Python</h4>
                         </a>
                         <p>About my first pull request in Python that got approved and merged.</p>
                     </div>
 
                     <div class="blog__entry">
-                        <a href="https://helenclx.github.io/blog/posts/2023-09-26-CS50x-Week-8-Assignments-Completed" target="blank">
+                        <a href="https://helenclx.github.io/blog/posts/2023-09-26-CS50x-Week-8-Assignments-Completed.html" target="blank">
                             <h4>CS50x Week 8 Assignments Completed</h4>
                         </a>
                         <p>I have completed and submitted the Week 8 assignment of the CS50's Introduction to Computer Science (CS50x) course.</p>
                     </div>
 
                     <div class="blog__entry">
-                        <a href="https://helenclx.github.io/blog/posts/2023-09-10-CS50x-Week-7-Completed" target="blank">
+                        <a href="https://helenclx.github.io/blog/posts/2023-09-10-CS50x-Week-7-Completed.html" target="blank">
                             <h4>CS50x Week 7 Completed</h4>
                         </a>
                         <p>I have completed and submitted the Week 7 assignment of the CS50's Introduction to Computer Science (CS50x) course.</p>