`INSERT` multiple JSON `CONTENT`s at once

[lvca]

Discussed in #1226

^{Originally posted by gramian September 1, 2023}
Dear All,
I would like to propose to extend the syntax of inserting JSON, ie:

INSERT INTO doc CONTENT { "name": "Jerry" };

such that it allows multiple record insertions in a single command, just like VALUES does.
This could look like:

INSERT INTO doc CONTENT { "name": "Jerry" }, { "num": 4 }, { "id": "x1" };

which would result in three records.