Update 'Data'

Data.md

@@ -1 +1,14 @@
+# Syntax
+
+```
+data ro integer:Int 3202
+
+data ro integerArrayInitialized:{Int 16}
+	3948 293 293049 948 912
+	340 0 2304 0 4785 92
+```
+
+Data sections are syntactically similar to blind typedef sections.
+
+# Semantics
 TODO