Add support for markdown in property description

[fbaligand]

On completion and hover on a property, it would be great that displayed description is rendered using markdown renderer (based on "description" property in json schema),

[remcohaszing]

This can already be achieved by using the "markdownDescription" field instead of the "description" field. However, I would like to store a markdown description in the "description" field. I use a schema that comes from an OpenAPI document, of which descriptions should be treated as markdown.

[ssbarnea]

Initially I was not sure if that would have being a good or bad idea, especially as we already support the markdownDescription field. But at the same time, I hardly can see any schema author/maintainer willing to support both plain-text and markdown versions. As markdown can also be read as plain text, the idea of assuming that description itself is markdown seems like a reasonable one.

Another benefit of using description itself is that we could use strict schema validation and make use of auto-complete for descriptions. Now we always have to remember to type the markdownDescription which is not part of the JSON Schema spec.

[remcohaszing]

~~@LoneDev6 that appears to be unrelated, and bug. Could you report a bug? Also I don’t see there that’s coming from. I’m open to a pull request.~~

Sorry, I misplaced the context. I do see markdownDescription show up in the autocompletion in VSCode, but not in Monaco YAML.

[LoneDev6]

Nvm, seems that the UX is just confusing because the > arrow is not shown if not hovered. The markdown is shown correctly.

https://user-images.githubusercontent.com/27242001/198031567-cd00f0ea-68fe-4e42-bd0f-e950e2af199d.mp4

Off-topic: I just wish there was a way to forcefully show the suggestion details panel using the vscode API, but seems there is no way. Let me know if you have a solution.