Mark a few more properties as readonly
Mark a few more properties as readonly

These are taken as object parameters. Making these `readonly` makes it clearer that these are only used as inputs to the function and not modifier

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