Document editable json_documents

- API pages for set and push_back of basic_json_document and for the
  editable aliases; the class overviews name the Editable parameter
- type_error.319 on the exceptions page
- the feature page explains editing, and the examples show when it
  helps: a configuration file changed without reformatting it

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

docs/mkdocs/docs/api/ordered_json_editable_view.md

@@ -0,0 +1,40 @@
+# <small>nlohmann::</small>ordered_json_editable_view
+
+<small>Defined in header `<nlohmann/json_view.hpp>`</small>
+
+```cpp
+using ordered_json_editable_view = basic_json_view<ordered_json, true>;
+```
+
+This type is a [`basic_json_view`](basic_json_view/index.md) of a value of an
+[`ordered_json_editable_document`](ordered_json_editable_document.md), the corresponding view for
+[`ordered_json_view`](ordered_json_view.md) the way [`json_editable_view`](json_editable_view.md) is for
+[`json_view`](json_view.md).
+
+## Examples
+
+??? example
+
+    The example below is the same as [`ordered_json_editable_document`'s](ordered_json_editable_document.md): the
+    views `set` returns see the document's member order preserved on `materialize()`, unlike for a
+    [`json_editable_document`](json_editable_document.md).
+
+    ```cpp
+    --8<-- "examples/ordered_json_editable_document.cpp"
+    ```
+
+    Output:
+
+    ```json
+    --8<-- "examples/ordered_json_editable_document.output"
+    ```
+
+## See also
+
+- [ordered_json_editable_document](ordered_json_editable_document.md) - the document type this view refers into
+- [ordered_json_view](ordered_json_view.md) - the corresponding read-only view
+- [json_editable_view](json_editable_view.md) - the corresponding view for `json_editable_document`
+
+## Version history
+
+Since version 3.13.0.