Brush tips/tutorials collection renames
At first I haven't even noticed that "Brush tips" means "Brush advice/tutorials" and they are not about actual "Brush tips". I think it would be good to avoid using such language since we have an actual technical term "Brush tip" that describes something very specific.
In any case, in this MR I changed:
- titles to not have
-and be nicer
- the index is more user-friendly now, too
- I added notes that they might be outdated (they are :( might be good to ask KA users to update those? Looks like easy task, good for first contribution)