anchor.diff:  %% <h2>Examples</h2>
   %% <h3>Elixir</h3>
   %% ```
  -%% iex> :syn.add_node_to_scopes([:devices]).
  +%% iex> :syn.add_node_to_scopes([:devices])
   %% :ok
   %% '''
   %% <h3>Erlang</h3>
  
positive.code: %% <h2>Examples</h2>
  %% <h3>Elixir</h3>
  %% ```
  %% iex> :syn.join(:devices, "area-1", self(), [meta: :one]).
  %% :ok
  %% '''
  %% <h3>Erlang</h3>
  
negative.code: %% ```
  %% iex> :syn.add_node_to_scopes([:users])
  %% :ok
  %% iex> pid = self()
  %% #PID<0.88.0>
  %% iex> :syn.join(:users, {:italy, :lombardy}, pid)
  %% :ok
  %% iex> :syn.members(:users, {:italy, :lombardy})
  %% [#PID<0.88.0>,:undefined}]
  %% iex> :syn.is_member(:users, {:italy, :lombardy}, pid)
  %% true
  