📝 add more API documentation

doc/mkdocs/docs/api/basic_json/get_to.md

@@ -0,0 +1,58 @@
+# basic_json::get_to
+
+```cpp
+template<typename ValueType>
+ValueType& get_to(ValueType& v) const noexcept(
+    noexcept(JSONSerializer<ValueType>::from_json(
+        std::declval<const basic_json_t&>(), v)))
+```
+
+Explicit type conversion between the JSON value and a compatible value. The value is filled into the input parameter by
+calling the `json_serializer<ValueType>` `from_json()` method.
+
+The function is equivalent to executing
+```cpp
+ValueType v;
+JSONSerializer<ValueType>::from_json(*this, v);
+```
+
+This overloads is chosen if:
+
+- `ValueType` is not `basic_json`,
+- `json_serializer<ValueType>` has a `from_json()` method of the form `void from_json(const basic_json&, ValueType&)`
+
+## Template parameters
+
+`ValueType`
+:   the value type to return
+
+## Return value
+
+the input parameter, allowing chaining calls
+
+## Exceptions
+
+Depends on what `json_serializer<ValueType>` `from_json()` method throws
+
+## Example
+
+??? example
+
+    The example below shows several conversions from JSON values to other types. There a few things to note: (1)
+    Floating-point numbers can be converted to integers, (2) A JSON array can be converted to a standard
+    `#!cpp std::vector<short>`, (3) A JSON object can be converted to C++ associative containers such as
+    `#cpp std::unordered_map<std::string, json>`.
+        
+    ```cpp
+    --8<-- "examples/get_to.cpp"
+    ```
+    
+    Output:
+    
+    ```json
+    --8<-- "examples/get_to.output"
+    ```
+
+## Version history
+
+- Since version 3.3.0.