Improve instructions/documentation for Fish Train pass

[icykoneko]

Particularly for the Fish Train pass page, if users are not familiar with the main tracker, they may not know what many of the icons actually mean. Perhaps a collapsible legend on the side for the icons indicating required tome, and aquarium type. Definitely do not want to many the UI too cluttered.

Consider including similar feature on the main tracker as well. Some of this is covered in the "Tips and Tricks" popup, but that's currently hidden away by the menu. A help icon might be more intuitive.