feat: update JSON builtin function %json_set to allow setting of _object_ and _subsequent object_

[The-Lum]

Hello PlantUML team,

To continue:

• Dynamically create a json structure inside the preprecessor function #328
• feat: add new JSON builtin functions (%str2json, %json_add and %json_remove) #1742
• fix: add int and string management on %json_add #1757
• feat: add new JSON builtin function (%json_set) #1761
• feat: add new JSON builtin function (%json_merge) #1763

Use of deepMerge from:

• feat: add new JSON Object method (deepMerge) on plantuml/json #1764
  [Thanks to @pbi-qfs]

To allow json_set for object and subsequent object.

Here is now a new example:

%json_set({"partlen": "2", "color": {"A":"red", "B":"blue"}}, {"color":{"A":"black"}}) '-> {"partlen":"2","color":{"A":"black","B":"blue"}}

To answer to:

• https://forum.plantuml.net/15436/allow-update-json-object-or-array-value

Regards,
Th.