Tweak animation file names to be less confusing in Creating the player scene

[Calinou]

• Follow-up to Fix animation name in Your first 2D game #9958.

It's more verbose, but it's easier to understand and doesn't rely on the reader knowing how to interpret the [1/2] part.

• See getting_started/first_2d_game/02.player_scene godot-docs-user-notes#105 (comment).

[Piralein]

It still reads confusing for me, maybe a bullet list works better in this case

On the left is a list of animations. Click the ``default`` one and rename it to
``walk``. Then click the "Add Animation" button to create a second animation named
``up``.

Find the player images in the FileSystem dock - they're in the ``art``
folder you unzipped earlier.
Drag the two images for each animation,
into the **Animation Frames** side of the panel for the corresponding animation:

* ``playerGrey_walk1`` and ``playerGrey_walk2`` for the ``walk`` animation
* ``playerGrey_up1`` and ``playerGrey_up2`` for the ``up`` animation

or maybe the and between the 2 animations

[mhilbrunner]

Thanks for following up on this, when cherry-picking the original I kinda agreed this could be improved further :)