[new]: `json_merge(json_string1, json_string2)`

[unytics]

Check the idea has not already been suggested

• I could not find my idea in existing issues

Edit the title above with self-explanatory function name and argument names

• The function name and the argument names I entered in the title above seems self explanatory to me.

BigFunction Description as it would appear in the documentation

inpired from https://github.com/djdhyun/bigquery-typescript-udf

Examples of (arguments, expected output) as they would appear in the documentation

json_merge('{"k1": "v1"}', '{"k2": "v2"}')
--> {"k1":"v1","k2":"v2"}