Move 'snippet' queries to 'snippets' folders

cpp/ql/examples/snippets/arrayaccess.ql

@@ -0,0 +1,16 @@
+/**
+ * @name Array access
+ * @description Finds array access expressions with an index expression
+ *              consisting of a postfix increment (`++`) expression.
+ * @tags array
+ *       access
+ *       index
+ *       postfix
+ *       increment
+ */
+
+import cpp
+
+from ArrayExpr a
+where a.getArrayOffset() instanceof PostfixIncrExpr
+select a