added shortcut to toggle ineditor comments

Summary:
Explained by the text.

Also refactored metric tracking to be handled on controller level.

Reviewed By: quark-zju

Differential Revision: D69379320

fbshipit-source-id: b02c0dc3bb1c5ad3d2ca6a9da2128f7bbdacb1e5

addons/vscode/package.json

@@ -205,6 +205,12 @@
         "key": "alt-shift-g",
         "mac": "alt-shift-g",
         "when": "isl.inlineCommentSidePanelEnabled && activeWebviewPanelId != 'sapling.comments'"
+      },
+      {
+        "command": "sapling.toggle-inline-comments",
+        "key": "alt-shift-t",
+        "mac": "alt-shift-t",
+        "when": "isl.inlineCommentSidePanelEnabled"
       }
     ],
     "menus": {