[Vis editor] Triple quote for multiline script support in JSON input

[kiju98]

Describe the feature:

It seems that the editor in Kibana 7.13.0+ supports the triple quote but Kibana Visualization doesn't support it.
It would be great if it's supported in Visualization so that we can use scripts easier.

Describe a specific use case for the feature:

Currently the normal quite works as below:

If we use unmatching quotes as below, we get a red bar on the right side:

The triple quote doesn't show the red bar in the right side but still the JSON input label turns red and the Update button shows Errors in the highlighted fields need to be resolved.

FYI, the triple quote is supported in Watcher and SearchProfiler (#57563)

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[timroes]

@stratoula The problem here is that when we migrated to monaco, we used XJSON as a language instead of JSON, thus the editor thinks we can do triple quotes, while we technically can't because we never treat that value actually as xJSON, but only JSON.

I think this is currently especially confusing, since our monaco integration doesn't even have JSON as a language, why a lot of people might fall back to using XJson thinking it's the same and then run into this problem. I've opened #107733 to track supporting JSON highlighting.

So we basically have two options: a) switch to JSON highlighting ones available or b) treat that value actually as xJSON and thus allow triple quotes in visualize.

[stratoula]

Yes I guessed so Tim, this is the reason I decided to open this issue. I think that we should try the second option first and if is not possible for any reason then switch to JSON highlighting