fix #1393: Always use local help to return cmdlet help text

If the user has overridden the Get-Help -Online parameter to always be
true, then calls to Get-Help will always launch a new browser window
to the cmdlet help. Instead, we want it to return the full cmdlet text
as intended, otherwise things like intellisense and tooltips may end
up opening the cmdlet help in a new browser window.

Author: deadlydog

src/PowerShellEditorServices/Services/PowerShellContext/Handlers/ShowHelpHandler.cs

@@ -62,7 +62,7 @@ public async Task<Unit> Handle(ShowHelpParams request, CancellationToken cancell
                     [System.Net.ServicePointManager]::SecurityProtocol = $oldSslVersion
                 }
 
-                return Microsoft.PowerShell.Core\Get-Help $CommandName -Full
+                return Microsoft.PowerShell.Core\Get-Help $CommandName -Full -Online:$false
                 ";
 
             string helpParams = request.Text;

src/PowerShellEditorServices/Services/PowerShellContext/Utilities/CommandHelpers.cs

@@ -139,6 +139,7 @@ public static async Task<string> GetCommandSynopsisAsync(
                 // We use .Name here instead of just passing in commandInfo because
                 // CommandInfo.ToString() duplicates the Prefix if one exists.
                 .AddParameter("Name", commandInfo.Name)
+                .AddParameter("Online", false)
                 .AddParameter("ErrorAction", "Ignore");
 
             var results = await powerShellContext.ExecuteCommandAsync<PSObject>(command, sendOutputToHost: false, sendErrorToHost: false).ConfigureAwait(false);