Updated nlohmann::basicjson::begin (markdown)

nlohmann::basicjson::begin.md

@@ -6,7 +6,7 @@ const_iterator cbegin() const;
 
 ## Description
 
-Returns an iterator to the first value in the JSON container. If the JSON container is empty, the returned iterator will be equal to `end()`.
+Returns an iterator to the first value in the JSON container. If the JSON container is empty, the returned iterator will be equal to [`end()`](https://github.com/nlohmann/json/wiki/nlohmann::basicjson::end).
 
 ![illustration of iterators](http://upload.cppreference.com/mwiki/images/1/1b/range-begin-end.svg)
 
@@ -20,7 +20,7 @@ Iterator to the first value. Note the return value its deferencabilty depends on
 
 | value type | deferenceable | description |
 | ---------- | ------------- | ----------- |
-| null       | no | `null` has no value, always equal to `end()` |
+| null       | no | `null` has no value, always equal to [`end()`](https://github.com/nlohmann/json/wiki/nlohmann::basicjson::end) |
 | boolean    | yes | iterator to the boolean value |
 | string     | yes | iterator to the string value |
 | number     | yes | iterator to the number value |
@@ -38,4 +38,4 @@ None. The function's noexcept-specification is `noexcept`.
 ## See also
 
 - [**end**, **cend**](https://github.com/nlohmann/json/wiki/nlohmann::basicjson::end)<br>
-  returns an iterator to the end
+  returns an iterator to the end