Make enums case-insensitive (#1149)

Author: christianliebel

index.html

@@ -492,6 +492,8 @@ <h3>
           <li>[=Strip leading and trailing ASCII whitespace=] from
           |json|["dir"].
           </li>
+          <li>[=ASCII lowercase=] |json|["dir"].
+          </li>
           <li>If [=text-direction list=] doesn't [=list/contain=]
           |json|["dir"], return.
           </li>
@@ -678,6 +680,8 @@ <h3>
           <li>[=Strip leading and trailing ASCII whitespace=] from
           |json|["display"].
           </li>
+          <li>[=ASCII lowercase=] |json|["display"].
+          </li>
           <li>If [=display modes list=] doesn't [=list/contain=]
           |json|["display"], return.
           </li>
@@ -740,6 +744,8 @@ <h3>
           <li>[=Strip leading and trailing ASCII whitespace=] from
           |json|["orientation"].
           </li>
+          <li>[=ASCII lowercase=] |json|["orientation"].
+          </li>
           <li>If |json|["orientation"] doesn't [=list/contain=] any of the
           [=orientation values=], return.
           </li>