Reorganize directories (#3462)

* 🦃 move files
* 🦃 rename doc folder to docs
* 🦃 rename test folder to tests

docs/mkdocs/docs/api/basic_json/find.md

@@ -0,0 +1,72 @@
+# <small>nlohmann::basic_json::</small>find
+
+```cpp
+// (1)
+iterator find(const typename object_t::key_type& key);
+const_iterator find(const typename object_t::key_type& key) const;
+
+// (2)
+template<typename KeyType>
+iterator find(KeyType&& key);
+template<typename KeyType>
+const_iterator find(KeyType&& key) const;
+```
+
+1. Finds an element in a JSON object with a key equivalent to `key`. If the element is not found or the
+   JSON value is not an object, `end()` is returned.
+2. See 1. This overload is only available if `KeyType` is comparable with `#!cpp typename object_t::key_type` and
+   `#!cpp typename object_comparator_t::is_transparent` denotes a type.
+
+## Template parameters
+
+`KeyType`
+:   A type for an object key other than [`json_pointer`](../json_pointer/index.md) that is comparable with
+    [`string_t`](string_t.md) using  [`object_comparator_t`](object_comparator_t.md).
+    This can also be a string view (C++17).
+
+## Parameters
+
+`key` (in)
+:   key value of the element to search for.
+    
+## Return value
+
+Iterator to an element with a key equivalent to `key`. If no such element is found or the JSON value is not an object,
+a past-the-end iterator (see `end()`) is returned.
+
+## Exception safety
+
+Strong exception safety: if an exception occurs, the original value stays intact.
+
+## Complexity
+
+Logarithmic in the size of the JSON object.
+
+## Notes
+
+This method always returns `end()` when executed on a JSON type that is not an object.
+
+## Examples
+
+??? example
+
+    The example shows how `find()` is used.
+    
+    ```cpp
+    --8<-- "examples/find__key_type.cpp"
+    ```
+    
+    Output:
+    
+    ```json
+    --8<-- "examples/find__key_type.output"
+    ```
+
+## See also
+
+- [contains](contains.md) checks whether a key exists
+
+## Version history
+
+1. Added in version 3.11.0.
+2. Added in version 1.0.0. Changed to support comparable types in version 3.11.0.