Add support for gd for VSCodeVim#529

This commit maps `gd` to VSCode's go to declaration action.

src/actions/actions.ts

@@ -1337,6 +1337,18 @@ class CommandExitVisualLineMode extends BaseCommand {
   }
 }
 
+@RegisterAction
+class CommandGoToDefinition extends BaseCommand {
+  modes = [ModeName.Normal]
+  keys = ["g", "d"]
+
+  public async exec(position: Position, vimState: VimState): Promise<VimState> {
+    vimState.focusChanged = true;
+    await vscode.commands.executeCommand("editor.action.goToDeclaration");
+    return vimState;
+  }
+}
+
 // begin insert commands
 
 @RegisterAction