Worksheet affecting .scala files

[nicolasstucki]

@tuvior noticed that now on each save action on VS Code (from the dotty project) the worksheet mode starts and inserts whitespaces in the file.

[nicolasstucki]

I tried it on the published version from lampepfl/dotty.g8 and this is not an issue under that setup. It is only an internal issue.

[Duhemm]

@nicolasstucki I don't think that worksheets have been published anywhere at the moment?

Here's a fix: #5244

[nicolasstucki]

You are right. Already tested the fix. It works as expected.