Convert make_names and make_event_factory to use json5 config format.

third_party/WebKit/Source/core/html/parser/HTMLTokenizerNames.json5

+{
+  metadata: {
+    namespace: "HTMLTokenizer",
+  },
+
+  data: [
+    {
+      name: "--",
+      Symbol: "dashDash",
+    },
+    "doctype",
+    {
+      name: "[CDATA[",
+      Symbol: "cdata",
+    },
+    // The symbol "public" conflicts with the C++ keyword.
+    {
+      name: "public",
+      Symbol: "publicString",
+    },
+    "system",
+  ],
+}