Silence errors about lack of empty lines after bullet points in Particles 2D tutorial

(cherry picked from commit 893d4dd0f191df283d274c8de1969f2619f7e53d)

tutorials/2d/particle_systems_2d.rst

@@ -287,11 +287,11 @@ randomness ratio.
 Emission Shapes
 ---------------
 
-ParticlesMaterials allow you to set an Emission Mask, which dictates 
-the area and direction in which particles are emitted. 
+ParticlesMaterials allow you to set an Emission Mask, which dictates
+the area and direction in which particles are emitted.
 These can be generated from textures in your project.
 
-Ensure that a ParticlesMaterial is set, and the Particles2D node is selected. 
+Ensure that a ParticlesMaterial is set, and the Particles2D node is selected.
 A "Particles" menu should appear in the Toolbar:
 
 .. image:: img/emission_shapes1.png
@@ -313,13 +313,18 @@ Three types of emission masks can be generated from a texture:
 
 -  Solid Pixels: Particles will spawn from any area of the texture,
    excluding transparent areas.
+
 .. image:: img/emission_mask_solid.gif
+
 -  Border Pixels: Particles will spawn from the outer edges of the texture.
+
 .. image:: img/emission_mask_border.gif
--  Directed Border Pixels: Similar to Border Pixels, but adds
-   extra information to the mask to give particles the ability to emit
-   away from the borders. Note that an ``Initial Velocity`` will need to 
+
+-  Directed Border Pixels: Similar to Border Pixels, but adds extra
+   information to the mask to give particles the ability to emit away
+   from the borders. Note that an ``Initial Velocity`` will need to
    be set in order to utilize this.
+
 .. image:: img/emission_mask_directed_border.gif
 
 Emission Colors
@@ -331,7 +336,7 @@ Once you click "OK", the mask will be generated and set to the ParticlesMaterial
 
 .. image:: img/emission_shapes4.png
 
-All of the values within this section have been automatically generated by the 
+All of the values within this section have been automatically generated by the
 "Load Emission Mask" menu, so they should generally be left alone.
 
 .. note:: An image should not be added to ``Point Texture`` or ``Color Texture`` directly.