Stub out doc comments for new symbols
diff --git a/docs/harfbuzz-docs.xml b/docs/harfbuzz-docs.xml
index 7a42d23..00113e9 100644
--- a/docs/harfbuzz-docs.xml
+++ b/docs/harfbuzz-docs.xml
@@ -180,7 +180,7 @@
         <title>Index of new symbols in 1.2.3</title>
         <xi:include href="xml/api-index-1.2.3.xml"><xi:fallback /></xi:include>
       </index>
-      <index id="api-index-1.3.3" role="1.3.3">
+      <index id="api-index-1-3-3" role="1.3.3">
         <title>Index of new symbols in 1.3.3</title>
         <xi:include href="xml/api-index-1.3.3.xml"><xi:fallback /></xi:include>
       </index>