fix(docs): scale navbar slanted borders with container height

The slanted SVG borders bridging the navbar's left and right pill
containers were sized with fixed pixels (w-[24px] h-[60px] /
xl:w-[29px] xl:h-[72px]). When users scale Chrome's default font size
above 16px, rem-based content inside the nav grows but the SVGs stay
fixed, leaving a visible wedge of page background at the top of the
join. Switch to h-full w-auto so the SVGs follow the container's
actual height while preserving their viewBox aspect ratio.

Author: samjulien

docs/components/layout/navbar.tsx

@@ -208,14 +208,14 @@ const Navbar = ({ pageTree }: NavbarProps) => {
             alt="Slanted end border"
             width={29}
             height={72}
-            className="hidden -ml-px dark:inline-block shrink-0 w-[24px] h-[60px] xl:w-[29px] xl:h-[72px] object-cover"
+            className="hidden -ml-px dark:inline-block shrink-0 h-full w-auto object-cover"
           />
           <Image
             src="/images/navbar/slanted-end-border-light.svg"
             alt="Slanted end border"
             width={29}
             height={72}
-            className="-ml-px dark:hidden shrink-0 w-[24px] h-[60px] xl:w-[29px] xl:h-[72px] object-cover"
+            className="-ml-px dark:hidden shrink-0 h-full w-auto object-cover"
           />
         </div>
 
@@ -225,14 +225,14 @@ const Navbar = ({ pageTree }: NavbarProps) => {
             alt="Slanted start border"
             width={29}
             height={72}
-            className="hidden -mr-px dark:inline-block shrink-0 w-[24px] h-[60px] xl:w-[29px] xl:h-[72px] object-cover"
+            className="hidden -mr-px dark:inline-block shrink-0 h-full w-auto object-cover"
           />
           <Image
             src="/images/navbar/slanted-start-border-light.svg"
             alt="Slanted start border"
             width={29}
             height={72}
-            className="-mr-px dark:hidden shrink-0 w-[24px] h-[60px] xl:w-[29px] xl:h-[72px] object-cover"
+            className="-mr-px dark:hidden shrink-0 h-full w-auto object-cover"
           />
 
           <div