Send the proper message, and it works...

Turns out was sending an object when it just wants a string.
Still need to figure out what string to get... I think this would make sense to be done like vscode-powershell.

src/client/extension.ts

@@ -11,7 +11,7 @@ import { fileURLToPath, sleep } from './utils'
 import { getDefaultPowerShellPath, getPlatformDetails } from './platform';
 import settings = require("./settings");
 import * as process from './process';
-import { EvaluateRequestMessage, IEvaluateRequestArguments, GetHelpRequestMessage, IGetHelpRequestArguments } from "./messages";
+import { EvaluateRequestMessage, IEvaluateRequestArguments, GetHelpRequestMessage } from "./messages";
 
 async function getCurrentSelection(mode: string) {
     let doc = await workspace.document
@@ -97,9 +97,7 @@ function startREPLProc(context: ExtensionContext, config: settings.ISettings, pw
         let cmdEvalLine = commands.registerCommand("powershell.evaluateLine", async () => doEval('n'));
         let cmdEvalSelection = commands.registerCommand("powershell.evaluateSelection", async () => doEval('v'));
         let cmdGetHelp = commands.registerCommand("powershell.getHelp", async () => {
-            const getHelpArgs: IGetHelpRequestArguments = {
-                expression: 'Get-Command',
-            }
+            const getHelpArgs: string = 'test'
             client.sendRequest(GetHelpRequestMessage, getHelpArgs)
             await proc.scrollToBottom()
         });

src/client/messages.ts

@@ -10,6 +10,3 @@ export interface IEvaluateRequestArguments {
     expression: string;
 }
 export const GetHelpRequestMessage = "powerShell/showHelp";
-export interface IGetHelpRequestArguments {
-    expression: string;
-}