enable proposed api flag
enable proposed api flag

eamodio/vscode,eamodio/vscode,microsoft/vscode,microsoft/vscode,microsoft/vscode,eamodio/vscode,eamodio/vscode,microsoft/vscode,microsoft/vscode,eamodio/vscode,microsoft/vscode,eamodio/vscode,eamodio/vscode,eamodio/vscode,eamodio/vscode,microsoft/vscode,microsoft/vscode,eamodio/vscode,microsoft/vscode,eamodio/vscode,microsoft/vscode,microsoft/vscode,eamodio/vscode,microsoft/vscode,microsoft/vscode,microsoft/vscode,microsoft/vscode,eamodio/vscode,eamodio/vscode,eamodio/vscode,eamodio/vscode,eamodio/vscode,microsoft/vscode,microsoft/vscode