docs: en: add a note about the current state of the VideoToolbox crop & scale filter.

Author: galad87

source/docs/en/latest/technical/video-videotoolbox.markdown

@@ -66,6 +66,8 @@ Additionally, the following filters will be run on the GPU when both hardware de
 
 It is common, particularly on lower-end hardware, for the CPU to be a bottleneck for the hardware video encoder. To minimize this effect, enable the hardware decoders, and disable any filters that you do not require and can't be run on the GPU.
 
+The VideoToolbox scaler can't properly scale the chroma channels, resulting in misplaced chroma positions (FB13755082). It's better to using it unless you need a low quality encode.
+
 ## Advanced options
 
 The VideoToolbox encoder has a limited set of advanced encoder options. Generally speaking, it is not recommended to change these parameters, as the built-in presets offer a good range of options for common uses.