Update BulbSunlight.md

docs/22.0/BulbSunlight.md

@@ -11,6 +11,10 @@
 |`renderer`|renderer    |Renderer to add this light to|
 |`angle`   |number      |Direction of the light       |
 
+This type of light is a directional light source which covers the entire renderer with shadows radiating in one direction. Directional lights always cast shadows. When attached to a renderer that is using soft shadows, the size of a sunlight's penumbra can be adjusted too. This is helpful when simulating broad light sources such as windows or fireplaces.
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+A light's intensity is typically a value from `0` to `1` but when using HDR rendering, a light's intensity can exceed `1` to represent very bright light sources. Lights can be affected by a normal map too, should one be set up, and a light's "height" over the normal map can be adjusted too which changes how strongly the normal mapping effect is.
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 When created, a `BulbSunlight` will be added to the given renderer. A light can be added (and removed) from multiple renderers as you see fit.
 
 ?> You must maintain a reference to a created `BulbSunlight` yourself. Bulb tracks lights using a **weak reference** such that when you discard the reference to the light, the light is also automatically removed from the renderer. This makes memory management a lot safer, but does require that you keep your own strong reference to keep a light alive.