Fix typos (#4362)

* Fix misspell.

* Add missing link title.

* Fix add missing word.

src/pages/about.astro

@@ -49,7 +49,7 @@ import BaseLayout from '../layouts/BaseLayout.astro';
           <p class='mb-3'>
             <span class='font-bold'>roadmap.sh</span> contains community-curated
             roadmaps, study plans, paths, and resources for developers. There are
-            role-based roadmaps, listing skills you should for any given role, as
+            role-based roadmaps, listing skills you should know for any given role, as
             well as skill-based roadmaps listing items to learn for any given skill.
           </p>
           <p class='mb-3'>