Fix long titles, multiple headings and redirect links

src/components/OpenSourceBanner.astro

@@ -7,7 +7,7 @@ const starCount = await getFormattedStars('kamranahmedse/developer-roadmap');
 
 <div class='py-6 sm:py-16 border-b border-t text-left sm:text-center bg-white'>
   <div class='max-w-[600px] container'>
-    <h1 class='text-3xl sm:text-5xl font-bold'>Open Source</h1>
+    <h2 class='text-3xl sm:text-5xl font-bold'>Open Source</h1>
     <p class='text-gray-600 text-sm sm:text-lg leading-relaxed my-2.5 sm:my-5'>
       The project is OpenSource, <a
         href='https://github.com/search?o=desc&q=stars%3A%3E100000&s=stars&type=Repositories'

src/components/RoadmapHeader.astro

@@ -42,7 +42,7 @@ const isRoadmapReady = !isUpcoming;
         {
           !hasSearch && (
             <>
-            <a href='/roadmaps' class='bg-gray-500 py-1.5 px-3 rounded-md text-white text-xs sm:text-sm font-medium hover:bg-gray-600' aria-label="Back to All Roadmaps">
+            <a href='/roadmaps/' class='bg-gray-500 py-1.5 px-3 rounded-md text-white text-xs sm:text-sm font-medium hover:bg-gray-600' aria-label="Back to All Roadmaps">
               &larr;<span class='hidden sm:inline'>&nbsp;All Roadmaps</span>
             </a>