refactor: adjust navbar item border-radius to 0.8rem (apify#1853)

Closes: https://github.com/apify/apify-web/issues/5173

Author: mstiglic

apify-docs-theme/src/theme/custom.css

@@ -934,7 +934,7 @@ div[class*="searchBox"] {
 .navbar__item > .navbar__link,
 .navbar-sidebar__back {
     padding: 0.8rem 1.2rem;
-    border-radius: 2rem;
+    border-radius: 0.8rem;
     font-size: 1.4rem;
     line-height: 2.4rem;
     font-weight: 500;