Hello @Brent Hollett,
Welcome to Microsoft Q&A forum.
Detailed rules for spell checking can be customized, but I don’t think, nor I find that it’s possible to turn off spell checking for one specific file.
There’s an option Edit > Advanced > Toggle Spell Checker. It controls the Spell Checker(turn on/turn off). VS also provides a button for quickly turn on/tun off the Spell Checker, it’s on toolbar. Maybe you can try to turn off the Spell Checker when you are focusing on the specified file and turn it on when you are not focusing on the specified file.
Best Regards,
Tianyu
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