HTML special characters not escaped in documentation tooltips

Describe the bug

If a JSON schema contains HTML characters (eg. <span>foo</span>) in the description field, those are not escaped before being handed over to VS Code, which apparently interprets them (probably to offer rich formatting).

Extension version: 0.11.1

Expected Behavior

HTML special chars like < get replaced by their entites (<) before being passed to VS Code

Current Behavior

HTML special chars are passed directly to VS Code.

This could actually be considered a feature, but I don't know if other tools reading the schema (eg. doc generators) play well with that...

Steps to Reproduce

1. Write a schema with <span>hello</span> in the description field
2. Hover a term in a YAML doc to invoke the documentation tooltip

Environment

• Windows
• Mac
• Linux
• other (please specify)