language tour: remove old 'automatic closures' page

[SethTisue]

fixes #3095

[Flowdalic]

FYI, https://docs.scala-lang.org/tour/automatic-closures.html still exists and is accessible. I am not sure if this should be the case.

[SethTisue]

@fsalvi is this one of those things where the website publishing only adds files but doesn't delete them?

do you have any clue why the redirect_from in this PR isn't doing its job...?

[fsalvi]

To avoid any disaster during the build & deploy job, the rsync command to the website doesn't delete existing files, this is why the file was still present. I forced it manually to delete, now the file is not present anymore and you get a 404 error.
The redirect_from works fine, but with the URI "/tutorials/tour/automatic-closures.html" (not /tour/automatic-closures.html).

[SethTisue]

thanks! added more redirects in 2728dd5