markdownEnumDescriptions don't remove markdown <backtick>##<backtick> in the settings UI and don't remove ## in settings.json

[sean-mcmanus]

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: 1.58.2
• OS Version: Windows

Steps to Reproduce:

1. View the files.autoSave, afterDelay enum description.

Bug: The `##` isn't removed:

In settings.json, ## isn't removed:

[roblourens]

@rzhao271 if you are going to move an issue to the backlog, please put labels on it