`html-language-features`: extension lacks embedded support

[vince-fugnitto]

Description

Follow-up from #35, it seems as though the packaging of html-language-features does not work well as embedded JS/TS support is non-existent (ex: quick suggestions).

It is likely a problem with how the extension is built/packaged as the same extension in vscode from open-vsx also does not have embedded support.

Example Videos

vscode (confirmed with all extensions disabled):

vscode-embedded.mp4

theia (confirmed with v1.50.0):

theia-embedded.mp4