Add comment operator 'gb'.

This commit make it possbile to use 'gb' to toggle line comments.

src/actions/actions.ts

@@ -7050,3 +7050,19 @@ class CommandSurroundAddToReplacement extends BaseCommand {
     return false;
   }
 }
+
+@RegisterAction
+export class CommentOperator extends BaseOperator {
+  public keys = ["g", "b"];
+  public modes = [ModeName.Normal, ModeName.Visual, ModeName.VisualLine];
+
+  public async run(vimState: VimState, start: Position, end: Position): Promise<VimState> {
+    vimState.editor.selection = new vscode.Selection(start.getLineBegin(), end.getLineEnd());
+    await vscode.commands.executeCommand("editor.action.commentLine");
+
+    vimState.cursorPosition = new Position(start.line, 0);
+    vimState.currentMode = ModeName.Normal;
+
+    return vimState;
+  }
+}