Reword g2 error message to be more clear to users

The G2 error was implemented to help users understand why their graphics were going haywire. Unfortunately it still leaves people mystified and we get comments asking what it means.

On discord there has been some discussion as to how to rework the error to be more user-friendly.

GOALS:

• Users understand what to do to fix the error
• Error is translated into the user's language

The specific issue is that g2 and the language files are tied to the game version (and to a lesser extent, objects, but those very rarely have breaking changes like g2 and language)
The reason the g2 is outdated is 99% because people download the portable version and copy only the exe and leave everything else.
If the language file is outdated, then one string will be (undefined string) and the rest of the game plays fine. If the g2 is outdated, most of the game's text becomes obfuscated. So I think it's fine to continue to only check g2

No files or tests are named; start by locating the G2 error handling and the language/version-checking code. Review how outdated G2 and language files are detected, then verify that the revised message explains how users can fix the problem and is available in the user's language.