_content/css: fix content auto-scrolling on selection

Fix content auto-scrolling when it’s being selected and the cursor is
less than 4.6875rem from the top border of browser view window

Fixes golang/go#52917

Change-Id: Ibf077bbeb3ba57ee425b1965e9e833ba66d11383
Reviewed-on: https://go-review.googlesource.com/c/website/+/409014
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
Reviewed-by: Zeke Lu <lvzecai@gmail.com>
Reviewed-by: Soham Dongargaonkar <sohamssd@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Jamal Carvalho <jamal@golang.org>

_content/css/styles.css

@@ -247,7 +247,6 @@ html,
 .Site {
   max-height: 100%;
   min-height: 100vh;
-  scroll-padding-top: 4.6875rem;
 }
 a,
 a:link,