Fix unintentional module import. (#1484)

Fixes PowerShell/vscode-powershell#715 by not getting command
documentation unless the module has already been imported.

src/PowerShellEditorServices/Services/TextDocument/Handlers/CompletionHandler.cs

@@ -117,6 +117,12 @@ public async Task<CompletionItem> Handle(CompletionItem request, CancellationTok
                 return request;
             }
 
+            // No details means the module hasn't been imported yet and Intellisense shouldn't import the module to get this info.
+            if (request.Detail is null)
+            {
+                return request;
+            }
+
             try
             {
                 await _completionResolveLock.WaitAsync(cancellationToken).ConfigureAwait(false);