When I put Marlin configuration files for tronxy X5SA PRO into platformIO the code had spelling or grammar squiggles through it. I. Disabled squiggles in platformIO but it did not remove all of them and the code will not compile
Unfortunately, you have not supplied us with enough information to help you out. 
Can you please post the error messages you are getting, use three backtick (`) characters to wrap code in please – it makes it easier to read and prevents some code being interpreted as control characters on here.
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Like this, please.
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Which version of Marlin source did you download, there’s a base version and a debug version. I think you will need the debug version.
Also, when you downloaded the Marlin source, did you attempt to compile it in its default state before you made any changes? If you do this, it at least lets you know if there are any errors before you start – it’s not unheard of!
Assuming the code compiles, then make your change(s) and recompile. Any errors are most likely now caused by the changes you made. Also, it’s usually best to make one change (or one feature change) at a time, rather than fixing everything at once.
Sorry about the lecture! 
(I work in IT Support, usually, pandemics permitting!)
The squiggles are coming from VCSode, not from PlatformIO. Usually you can ignore them as it sometimes takes a first compilation to get rid. Plus, while “intellisense” is getting better, it’s not 100% there yet. It’s a lot better than nothing though, and still useful.
Cheers,
Norm.