Added itemprop for servo Metadata API

CJ8664 · web-flow · commit 3608690d3e01 · 2017-10-19T16:03:44.000-04:00
diff --git a/markup5ever/local_names.txt b/markup5ever/local_names.txt
@@ -420,6 +420,7 @@ irrelevant
 isindex
 ismap
 itemscope
+itemprop
 k
 k1
 k2
