fix a compatibility issue with doxygen

doc/faq.md

@@ -106,59 +106,59 @@
 
    Call one of the `SetXXX()` methods - they call destructor which deallocates DOM data:
 
-   ```
+   ~~~~~~~~~~cpp
    Document d;
    ...
    d.SetObject();  // clear and minimize
-   ```
+   ~~~~~~~~~~
 
    Alternatively, use equivalent of the [C++ swap with temporary idiom](https://en.wikibooks.org/wiki/More_C%2B%2B_Idioms/Clear-and-minimize):
-   ```
+   ~~~~~~~~~~cpp
    Value(kObjectType).Swap(d);
-   ```
+   ~~~~~~~~~~
    or equivalent, but sightly longer to type:
-   ```
+   ~~~~~~~~~~cpp
    d.Swap(Value(kObjectType).Move()); 
-   ```
+   ~~~~~~~~~~
 
 9. How to insert a document node into another document?
 
    Let's take the following two DOM trees represented as JSON documents:
-   ```
+   ~~~~~~~~~~cpp
    Document person;
    person.Parse("{\"person\":{\"name\":{\"first\":\"Adam\",\"last\":\"Thomas\"}}}");
    
    Document address;
    address.Parse("{\"address\":{\"city\":\"Moscow\",\"street\":\"Quiet\"}}");
-   ```
+   ~~~~~~~~~~
    Let's assume we want to merge them in such way that the whole `address` document becomes a node of the `person`:
-   ```
+   ~~~~~~~~~~js
    { "person": {
       "name": { "first": "Adam", "last": "Thomas" },
       "address": { "city": "Moscow", "street": "Quiet" }
       }
    }
-   ```
+   ~~~~~~~~~~
 
    The most important requirement to take care of document and value life-cycle as well as consistent memory managent using the right allocator during the value transfer.
    
    Simple yet most efficient way to achieve that is to modify the `address` definition above to initialize it with allocator of the `person` document, then we just add the root nenber of the value:
-   ```
+   ~~~~~~~~~~cpp
    Documnet address(person.GetAllocator());
    ...
    person["person"].AddMember("address", address["address"], person.GetAllocator());
-   ```
+   ~~~~~~~~~~
 Alternatively, if we don't want to explicitly refer to the root value of `address` by name, we can refer to it via iterator:
-   ```
+   ~~~~~~~~~~cpp
    auto addressRoot = address.MemberBegin();
    person["person"].AddMember(addressRoot->name, addressRoot->value, person.GetAllocator());
-   ```  
+   ~~~~~~~~~~
    
    Second way is to deep-clone the value from the address document:
-   ```
+   ~~~~~~~~~~cpp
    Value addressValue = Value(address["address"], person.GetAllocator());
    person["person"].AddMember("address", addressValue, person.GetAllocator());
-   ```
+   ~~~~~~~~~~
 
 ## Document/Value (DOM)