Refactor markdown extension removal logic

Support for `.md`, `.mdx`, and `index.md(x)` variations. This should make it easier to link things moving forward.

Author: khalidabuhakmeh

src/plugins/remove-markdown-extensions.ts

@@ -19,17 +19,15 @@ export default function removeMarkdownExtensions(): (tree: Node) => void {
         node.properties &&
         typeof node.properties.href === "string"
       ) {
-        const markdownExtensionRegex = /\.md(#.*)?$/;
-        if (markdownExtensionRegex.test(node.properties.href)) {
+        const match = /(?:\/index)?\.(md|mdx)(#.*)?$/;
+        if (match.test(node.properties.href)) {
           let date = new Date().toLocaleTimeString("en-US", { hour12: false });
+
           console.log(
-            `\x1b[90m${date}\x1b[0m \x1b[95m[🔥 *.md]\x1b[0m ${node.properties.href}`,
+            `\x1b[90m${date}\x1b[0m \x1b[95m[🔥 *.md(x)]\x1b[0m ${node.properties.href}`,
           );
 
-          node.properties.href = node.properties.href.replace(
-            markdownExtensionRegex,
-            "$1",
-          );
+          node.properties.href = node.properties.href.replace(match, "$2");
         }
       }
     });