fix: Adjust markdown links to correct level (#255)

Co-authored-by: Dominik Dorfmeister <office@dorfmeister.cc>

app/components/MarkdownLink.tsx

@@ -2,13 +2,15 @@ import { Link } from '@tanstack/react-router'
 import type { HTMLProps } from 'react'
 
 export function MarkdownLink(props: HTMLProps<HTMLAnchorElement>) {
-  if ((props as { href: string }).href?.startsWith('http')) {
+  if (props.href?.startsWith('http')) {
     return <a {...props} />
   }
 
+  const relativeHref = props.href?.replace(/([A-Za-z][A-Za-z/_-]+).md/, '../$1')
+
   return (
     <Link
-      to={props.href as any}
+      to={relativeHref}
       params={{}}
       {...props}
       preload={undefined}