LibWeb: Introduce the concept of "Enumerated" values

This does _NOT_ correspond to anything in the IDL or ECMAScript spec,
but is a custom extended attribute.
We use it to define the "enumerated" values of an attribute

Userland/Libraries/LibWeb/HTML/HTMLButtonElement.idl

@@ -1,6 +1,13 @@
 #import <HTML/HTMLElement.idl>
 #import <HTML/HTMLFormElement.idl>
 
+[MissingValueDefault=submit, InvalidValueDefault=submit]
+enum ButtonTypeState {
+    "submit",
+    "reset",
+    "button"
+};
+
 // https://html.spec.whatwg.org/multipage/semantics.html#htmlbuttonelement
 [Exposed=Window]
 interface HTMLButtonElement : HTMLElement {
@@ -14,7 +21,7 @@ interface HTMLButtonElement : HTMLElement {
     [CEReactions, Reflect=formnovalidate] attribute boolean formNoValidate;
     [CEReactions, Reflect=formtarget] attribute DOMString formTarget;
     [CEReactions, Reflect] attribute DOMString name;
-    [CEReactions, Reflect] attribute DOMString type;
+    [CEReactions, Reflect, Enumerated=ButtonTypeState] attribute DOMString type;
     [CEReactions, Reflect] attribute DOMString value;
 
     // FIXME: readonly attribute boolean willValidate;

Userland/Libraries/LibWeb/HTML/HTMLMediaElement.idl

@@ -3,6 +3,7 @@
 #import <HTML/MediaError.idl>
 #import <HTML/TimeRanges.idl>
 #import <HTML/VideoTrackList.idl>
+#import <HTML/Scripting/Fetching.idl>
 
 enum CanPlayTypeResult {
     "",
@@ -21,7 +22,7 @@ interface HTMLMediaElement : HTMLElement {
     [Reflect, CEReactions] attribute DOMString src;
     // FIXME: attribute MediaProvider? srcObject;
     readonly attribute USVString currentSrc;
-    [Reflect=crossorigin, CEReactions] attribute DOMString? crossOrigin;
+    [Reflect=crossorigin, CEReactions, Enumerated=CORSSettingsAttribute] attribute DOMString? crossOrigin;
     const unsigned short NETWORK_EMPTY = 0;
     const unsigned short NETWORK_IDLE = 1;
     const unsigned short NETWORK_LOADING = 2;

Userland/Libraries/LibWeb/HTML/HTMLScriptElement.idl

@@ -1,4 +1,5 @@
 #import <HTML/HTMLElement.idl>
+#import <HTML/Scripting/Fetching.idl>
 
 // https://html.spec.whatwg.org/multipage/scripting.html#htmlscriptelement
 [Exposed=Window]
@@ -11,7 +12,7 @@ interface HTMLScriptElement : HTMLElement {
     [CEReactions, Reflect=nomodule] attribute boolean noModule;
     // FIXME: [CEReactions] attribute boolean async;
     [CEReactions, Reflect] attribute boolean defer;
-    [CEReactions, Reflect=crossorigin] attribute DOMString? crossOrigin;
+    [CEReactions, Reflect=crossorigin, Enumerated=CORSSettingsAttribute] attribute DOMString? crossOrigin;
     // FIXME: [CEReactions] attribute DOMString text;
     [CEReactions, Reflect] attribute DOMString integrity;
     [CEReactions, Reflect=referrerpolicy] attribute DOMString referrerPolicy;

Userland/Libraries/LibWeb/HTML/Scripting/Fetching.idl

@@ -0,0 +1,7 @@
+// https://html.spec.whatwg.org/multipage/urls-and-fetching.html#cors-settings-attribute
+[MissingValueDefault=, InvalidValueDefault=anonymous]
+enum CORSSettingsAttribute {
+    "anonymous",
+    "",
+    "use-credentials"
+};

Userland/Libraries/LibWeb/SVG/SVGScriptElement.idl

@@ -1,8 +1,10 @@
+#import <HTML/Scripting/Fetching.idl>
+
 // https://www.w3.org/TR/SVG/interact.html#InterfaceSVGScriptElement
 [Exposed=Window]
 interface SVGScriptElement : SVGElement {
     [Reflect] attribute DOMString type;
-    [Reflect=crossorigin] attribute DOMString? crossOrigin;
+    [Reflect=crossorigin, Enumerated=CORSSettingsAttribute] attribute DOMString? crossOrigin;
 };
 
 // FIXME: SVGScriptElement includes SVGURIReference;