message: memo: documented JSON Merge Patch (RFC 7386)
diff: - [STL-like access](#stl-like-access)
  - [Conversion from STL containers](#conversion-from-stl-containers)
  - [JSON Pointer and JSON Patch](#json-pointer-and-json-patch)
  + - [JSON Merge Patch](#json-merge-patch)
  - [Implicit conversions](#implicit-conversions)
  - [Conversions to/from arbitrary types](#arbitrary-types-conversions)
  - [Binary formats (CBOR, MessagePack, and UBJSON)](#binary-formats-cbor-messagepack-and-ubjson)
  @@ -456,6 +457,37 @@ json::diff(j_result, j_original);
  // ]
  ```
  +### JSON Merge Patch
  +
  +The library supports **JSON Merge Patch** ([RFC 7386](https://tools.ietf.org/html/rfc7386)) as a patch format. Instead of using JSON Pointer (see above) to specify values to be manipulated, it describes the changes using a syntax that closely mimics the document being modified.
  +
  +```cpp
  +// a JSON value
  +json j_document = R"({
  + "a": "b",
  + "c": {
  + "d": "e",
  + "f": "g"
  + }
  +})"_json;
  +
  +// a patch
  +json j_patch = R"({
  + "a":"z",
  + "c": {
  + "f": null
  + }
  +})"_json;
  +
  +// apply the patch
  +j_original.merge_patch(j_patch);
  +// {
  +// "a": "z",
  +// "c": {
  +// "d": "e"
  +// }
  +// }
  +```
  ### Implicit conversions
  