Fix typo in LandingNav.tsx

Author: jhollowe

src/components/LandingNav.tsx

@@ -48,7 +48,7 @@ export function LandingNav() {
                 </Link>)}
             <ThemeToggle />
             <Link to="/auth">
-              <Button size="sm">Sign Up/Sing In </Button>
+              <Button size="sm">Sign Up/Sign In </Button>
             </Link>
           </div>
 
@@ -76,4 +76,4 @@ export function LandingNav() {
         </div>
       </div>
     </nav>;
-}
+}