Add set for item-summoning statues

[richelbilderbeek]

Dear author of the super-useful online TerraMap,

With this Pull Request I suggest to add a set called 'Item spawning statues', which is the same set as https://terraria-archive.fandom.com/wiki/Statues#Item_Spawning_Statues. I don't know how to test this, but hey, I did take good care when writing the code :-)

This PR would save me and my girlfriend a lot of time hunting for these statues :-)

Cheers, Richel Bilderbeek

[jasoncoon]

Thanks for the PR!

I also fixed a long standing problem where selecting a set would highlight tiles, but not work with the find next / previous buttons.

[richelbilderbeek]

@jasoncoon thanks for accepting! My girlfriend and I already use this feature a lot! Keep up the good work 👍