Tab complete for [PSCustomObject] tab completes [System.Management.Automation.PSCustomObject]

System Details

• Operating system name and version: Windows 10 Enterprise
• VS Code version: 1.19.1
• Shell: 1.79
• Output from $PSVersionTable:
  Name Value

PSVersion 5.1.15063.726
PSEdition Desktop
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0...}
BuildVersion 10.0.15063.726
CLRVersion 4.0.30319.42000
WSManStackVersion 3.0
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1

$pseditor.EditorServicesVersion

Major  Minor  Build  Revision
-----  -----  -----  --------
1      5      1      0

code --list-extensions --show-versions
GrapeCity.gc-excelviewer@2.0.16
ms-vscode.PowerShell@1.5.1

$PSVersionTable

Name                           Value
----                           -----
PSVersion                      5.1.15063.726
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.15063.726
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

### Issue Description

Tab complete for [PSCustomO tab completes [System.Management.Automation.PSCustomObject]. This is a problem because [System.Management.Automation.PSCustomObject] cannot be used like:

[PSCustomObject]@{'Property' = $value}

### Attached Logs

Start by reproducing the tab-completion behavior in the VS Code PowerShell extension with the reported [PSCustomO expression and the provided PowerShell version. Trace the extension's completion behavior and verify that the short type name remains usable in the reported object-construction example.