Formatting and check-formatted still not always consistent

[dfalling]

Environment

• Elixir version (elixir -v): 1.17.1
• Phoenix version (mix deps): 1.7.18
• Phoenix LiveView version (mix deps): 1.0.1
• Operating system: macOS 15.0
• Browsers you attempted to reproduce this bug on (the more the merrier): n/a
• Does the problem persist after removing "assets/node_modules" and trying again? Yes/no: yes

Actual behavior

Formatter should format all code in a single pass that will then be accepted by mix format --check-formatted

(related to #3544)

Expected behavior

Formatter has to be run twice to get code to a state where it passes the check.

Example

starting code:

  def input(%{type: "select"} = assigns) do
    ~H"""
    <select>
      <option :if={@prompt} value="" class="dark:!text-white">{@prompt}</option>
      <!-- TODO: set color to below options somehow -->
      {IdoWeb.SlimSelectForm.options_for_select(@options, @value, "dark:!text-white")}
    </select>
    """
  end

with mix.format:

  def input(%{type: "select"} = assigns) do
    ~H"""
    <select>
      <option :if={@prompt} value="" class="dark:!text-white">{@prompt}</option>
      <!-- TODO: set color to below options somehow -->
      {IdoWeb.SlimSelectForm.options_for_select(@options, @value, "dark:!text-white")}

    </select>
    """
  end

(and mix format --check-formatted will error:

 396  396  |      {IdoWeb.SlimSelectForm.options_for_select(@options, @value, "dark:!text-white")}
 397  397  |
      398 +|
      399 +|
 398  400  |    </select>
 399  401  |    """
           |

If I run mix.format again, it will add those two extra lines that the check-formatted wants, and then everything passes.

If I remove the line with the TODO comment, the formatting works (and the blank lines before the </select> are removed.

[SteffenDE]

cc @josevalim (and maybe @feliperenan)