node: add lookupPrefix method (NOT TESTED)

Signed-off-by: Francis Bouvier <francis.bouvier@gmail.com>

src/netsurf.zig

@@ -383,6 +383,21 @@ pub fn nodeIsSameNode(node: *Node, other: *Node) bool {
     return res;
 }
 
+pub fn nodeLookupPrefix(node: *Node, namespace: ?[]const u8) ?[]const u8 {
+    if (namespace == null) {
+        return null;
+    }
+    if (std.mem.eql(u8, namespace.?, "")) {
+        return null;
+    }
+    var s: ?*String = undefined;
+    _ = nodeVtable(node).dom_node_lookup_prefix.?(node, stringFromData(namespace.?), &s);
+    if (s == null) {
+        return null;
+    }
+    return stringToData(s.?);
+}
+
 pub fn nodeNormalize(node: *Node) void {
     _ = nodeVtable(node).dom_node_normalize.?(node);
 }