Update LSP config example in README (#19)

Updated PowerShell Editor Services configuration with new binary path
and arguments.

The LSP config example shown in README doesn't work as far as I can tell
since there is no PowerShell Editor Services binary we could point to.

The commit uses a way to configure it as shown in [this
comment](wingyplus#16 (comment)).

Author: redactedscribe

README.md

@@ -12,11 +12,20 @@ If you wish to specify a custom path to your language server, you can do so via
 ```json
 {
     "lsp": {
-        "powershell-es": {
-            "binary": {
-                "path": "<path to PowerShellEditorServices>"
-            }
-        }
+		"powershell-es": {
+			"binary": {
+				"path": "pwsh.exe",
+				"arguments": [
+					"-NoLogo",
+					"-NoProfile",
+					"-Command",
+					"path\\to\\PowerShellEditorServices\\Start-EditorServices.ps1",
+					"-Stdio",
+					"-SessionDetailsPath",
+					"path\\to\\PowerShellEditorServices\\powershell-es.session.json",
+				],
+			},
+		},
     }
 }
 ```