📝 make examples collapsible

doc/mkdocs/docs/features/iterators.md

@@ -0,0 +1,129 @@
+# Iterators
+
+## Overview
+
+A JSON value is a container and allows access via iterators. 
+
+![](../images/range-begin-end.svg)
+
+![](../images/range-rbegin-rend.svg)
+
+## Iterator getters
+
+### `begin()`
+
+??? example
+
+    The following code shows an example for `begin()`.
+
+    ```cpp
+    --8<-- "examples/begin.cpp"
+    ```
+    
+    Output:
+
+    ```json
+    --8<-- "examples/begin.output"
+    ```
+
+### `cbegin()`
+
+??? example
+
+    The following code shows an example for `cbegin()`.
+
+    ```cpp
+    --8<-- "examples/cbegin.cpp"
+    ```
+    
+    Output:
+
+    ```json
+    --8<-- "examples/cbegin.output"
+    ```
+
+### `end()`
+
+??? example
+
+    The following code shows an example for `end()`.
+
+    ```cpp
+    --8<-- "examples/end.cpp"
+    ```
+    
+    Output:
+
+    ```json
+    --8<-- "examples/end.output"
+    ```
+
+### `cend()`
+
+??? example
+
+    The following code shows an example for `cend()`.
+
+    ```cpp
+    --8<-- "examples/cend.cpp"
+    ```
+    
+    Output:
+
+    ```json
+    --8<-- "examples/cend.output"
+    ```
+
+### `rbegin()`
+
+??? example
+
+    The following code shows an example for `rbegin()`.
+
+    ```cpp
+    --8<-- "examples/rbegin.cpp"
+    ```
+    
+    Output:
+
+    ```json
+    --8<-- "examples/rbegin.output"
+    ```
+
+### `rend()`
+
+??? example
+
+    The following code shows an example for `rend()`.
+
+    ```cpp
+    --8<-- "examples/rend.cpp"
+    ```
+    
+    Output:
+
+    ```json
+    --8<-- "examples/rend.output"
+    ```
+
+### `items()`
+
+??? example
+
+    The following code shows an example for `items()`.
+
+    ```cpp
+    --8<-- "examples/items.cpp"
+    ```
+    
+    Output:
+
+    ```
+    --8<-- "examples/items.output"
+    ```
+
+## Iterator invalidation
+
+| Operations | invalidated iterators |
+| ---------- | --------------------- |
+| `clear`    | all                   |