Add key binding for Show Additional Commands (#1233)

* Add key binding for Show Additional Commands

Adds default keyboard shortcut Ctrl-Alt-A for "Show Additional Commands from Modules".

* Change hotkey

Avoid using Ctrl-Alt combo as these can be problematic

Author: dsolodow

package.json

@@ -69,6 +69,11 @@
         "key": "shift+alt+e",
         "when": "editorTextFocus && editorLangId == 'powershell'"
       },
+      {
+        "command": "PowerShell.ShowAdditionalCommands",
+        "key": "shift+alt+s",
+        "when": "editorTextFocus && editorLangId == 'powershell'"
+      },
       {
         "command": "PowerShell.RunSelection",
         "key": "f8",