Steps to reproduce

Start a path to a command, in this case,

cd \\svr\

Press CTRL-SPACE (<-EDITED) to bring up completion suggestions, which list all the shares on '\\svr\'.

Select a share that contains a space (notice the highlight fails to clear off entries as you move through the list).

Expected behavior

quotes (') should be added around the UNC path which contains characters that need escaped or quoted.

Actual behavior

Immediately you will notice there is no quote characters being inserted into the completion, and this prevents completing the next step in the path.

Side note, Windows PowerShell 5.1 seems to have the same problem with UNC paths, but at least the highlight works correctly.

Environment data

> $PSVersionTable
Name                           Value
----                           -----
PSVersion                      6.0.3
PSEdition                      Core
GitCommitId                    v6.0.3
OS                             Microsoft Windows 10.0.17134
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0