Merge pull request #42838 from Calinou/doc-omni-spot-light-limitations

Document OmniLight/SpotLight rendering limitations

doc/classes/OmniLight.xml

@@ -5,6 +5,7 @@
 	</brief_description>
 	<description>
 		An Omnidirectional light is a type of [Light] that emits light in all directions. The light is attenuated by distance and this attenuation can be configured by changing its energy, radius, and attenuation parameters.
+		[b]Note:[/b] Due to current rendering engine limitations, only 8 OmniLights may affect a single mesh [i]resource[/i] at once. Consider splitting your level into several meshes to decrease the likelihood that more than 8 lights will affect the same mesh resource. Splitting the level mesh will also improve frustum culling effectiveness, leading to greater performance.
 	</description>
 	<tutorials>
 		<link>https://docs.godotengine.org/en/latest/tutorials/3d/lights_and_shadows.html</link>

doc/classes/SpotLight.xml

@@ -5,6 +5,7 @@
 	</brief_description>
 	<description>
 		A Spotlight is a type of [Light] node that emits lights in a specific direction, in the shape of a cone. The light is attenuated through the distance. This attenuation can be configured by changing the energy, radius and attenuation parameters of [Light].
+		[b]Note:[/b] Due to current rendering engine limitations, only 8 SpotLights may affect a single mesh [i]resource[/i] at once. Consider splitting your level into several meshes to decrease the likelihood that more than 8 lights will affect the same mesh resource. Splitting the level mesh will also improve frustum culling effectiveness, leading to greater performance.
 	</description>
 	<tutorials>
 		<link>https://docs.godotengine.org/en/latest/tutorials/3d/lights_and_shadows.html</link>