Add showTextDocument(uri|file)

This reverts commit 552957ee.

Fix multi-workspace support detection

#30955 Implement virtual editor for workspace settings in MR workspace

The inner container may not be created/attached yet.

Fixes #31235

* register new included languages in emmet on the fly

* no need to export the function

* only register default completion on startup

* fix tests

Group search results by root folders