Techtrees - make commas and ampersand translatable

[GunChleoc]

In the upgrade screens, affected units are listed and commas + ampersand added automatically by the script:



I am working on a translation for Scottish Gaelic, which uses ₇ instead of &. I imagind if we get people translation into languages that don't use Latin script, like Arabic or Chinese, they will have issues with this as well, and with the commas.

Maybe do away with the ampersand and have a comma instead, and then make the comma translatable?