More efficient way of finding files that may need to be formatted #284

Job	Run time
No Warnings	55s
Run Tests	1m 15s
Check Formatting	21s
Check TODOs	15s
Builds Playground	1m 4s
Test CSharpier.MSBuild (ubuntu-latest)	1m 34s
Test CSharpier.MSBuild (windows-latest)	2m 2s
	7m 26s

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