Wiki - Add comment about userdoc

[VaclavElias]

https://stride-docs-test.azurewebsites.net/latest/en/manual/scripts/public-properties-and-fields.html#adding-property-descriptions

Add this comment so one can understand what it means when generating Stride docs, that this xml tag is not for a docs but for the Stride Studio..

[manio143]

If I remember correctly, <summary> is used for XML comments (normal C# way of doing things), but there's a custom comments processor which reads <userdoc> and outputs a simplified file (not XML) that is read by GameStudio. There was a PR in the last two years which enabled GameStudio to also read XML comments.

[VaclavElias]

Thank you. That will help to clarify my updates.