Fix React warning

Author: Tommy Lillehagen

src/css/custom.css

@@ -15,7 +15,7 @@
   --ifm-color-primary-lighter: #fc8c46;
   --ifm-color-primary-lightest: #fca570;
   --ifm-button-background-color: #f8f8f8;
-  --ifm-button-border-color: #dadada;
+  --ifm-button-border-color: #e4e4e4;
   --ifm-button-color: #404040;
   --ifm-button-hover-background-color: #f2f2f2;
   --ifm-button-hover-border-color: #c8c8c8;

src/pages/index.js

@@ -166,14 +166,12 @@ export default function Home() {
                 Hack supports a rich set of <a href="https://docs.hhvm.com/hack/types/generic-types">generic types</a>,
                 including:
               </p>
-              <p>
-                <ul>
-                  <li><a href="https://docs.hhvm.com/hack/generics/type-parameters">type parameters</a>,</li>
-                  <li><a href="https://docs.hhvm.com/hack/generics/type-constraints">constraints</a>,</li>
-                  <li>associated <a href="https://docs.hhvm.com/hack/classes/type-constants-revisited">type constants</a>,</li>
-                  <li>and even <a href="https://docs.hhvm.com/hack/generics/reified-generics">reification</a>.</li>
-                </ul>
-              </p>
+              <ul>
+                <li><a href="https://docs.hhvm.com/hack/generics/type-parameters">type parameters</a>,</li>
+                <li><a href="https://docs.hhvm.com/hack/generics/type-constraints">constraints</a>,</li>
+                <li>associated <a href="https://docs.hhvm.com/hack/classes/type-constants-revisited">type constants</a>,</li>
+                <li>and even <a href="https://docs.hhvm.com/hack/generics/reified-generics">reification</a>.</li>
+              </ul>
             </div>
           </div>
           <div className="col col--7">