hide-able property for pre-requisite technologies

[Honktown]

It has been brought up some threads, that technologies either have prerequisites completely filled and may clutter the tech tree, or don't and create slightly unintended behavior (they can be researched out-of-sequence if science packs are acquired somehow). 'physical-projectile-damage-2' is an example.

A suggestion is to have a hide-able property. Implementation is left to the reader.

One way: Change the prototype prerequisite strings slightly so that they follow info.json "dependency" pattern. A string starting with '(?) ' would be a hidden dependency. '? ' alone doesn't need to mean anything, could mean the same, or could even permit "I want this as a prerequisite if it exists", applied after running data-final-fixes.

Any change may need separating the appearance of the tech tree from being the exact same as the prerequisite chain, if that isn't the case yet.

Goal: to still have prerequisites for technologies, such as science packs, equipment, recipes, etc, in-order but permit a technology chain to be highlighted independently or at least less cluttered. Downside: if a recipe contains a hidden prerequisite ingredient, it's not immediately obvious that is the reason the technology is unavailable, BUT, this feels better than the case where they can complete a technology and have a recipe they can't use.