`gui/unit-syndromes` - inspect selected unit, show history of infections

[amade-w]

1. The majority of the time, I'd use this tool to inspect what syndrome has affected a unit attacked by a forgotten beast in the caverns. The unit is usually an unnamed generic unit, so searching for it in a list is impractical; a workaround I use is to nickname the unit before searching it in gui/unit-syndromes. I suggest making gui/unit-syndromes inspect the currently selected unit by default. If none is selected, open the unit browser as per current behavior.

2. The tool only displays currently active syndromes. It might be useful to show the unit's history of syndrome infections as well (syndromes.reinfection_type and syndromes.reinfection_count).