chore: system.json changes, other superficial changes

[anthonyronda]

• I'm now mildly confident that V11 will not blow up in our faces. I'd like to set our maximum compatible version to 11 a bit earlier than last time, because I think that's best for devs and it's going to be fine for users. There will be a warning that they can't migrate their worlds back to V10
• The core library for Simplified Chinese has a different than expected language tag. This corrects the system.json lang key to the correct value
• Package description and sidebar text updated to use some borrowed OSE marketing copy. Trademark has been permitted for use under contract but I'm only just now doing some housekeeping because someone brought it up on Discord recently

[anthonyronda]

It occurred to me that Gavin doesn't use the OSR label anywhere (only Basic/Expert), and it was also a personal goal not to use the OSR label anywhere for UFT, so I'd like to retract that bit

[anthonyronda]

using h3 because in the settings tab screenshot, General Information and Game Settings are h2's

Added padding because we're already inheriting some padding, and I thought this looked more intentional. The top is only weird because of the overflowing span element where the version number is supposed to be. There is indeed a nice looking padding at the top as well

[anthonyronda]

Also I want to point out that I don't think UFT is inheriting any of this :)