Use char-based override instead of string in EndsWith

[Thorium]

Tiny code clean-up.

Fix for CA1865-1867: https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/quality-rules/ca1865-ca1867

[cartermp]

Some tests failing!

[Thorium]

Oh, of course .LastIndexOf "/" = 0 is rather .StartsWith rather than .EndsWith, however it's a weird StartsWith because it's not StartsWith if there are more than one /. I was hoping not to go the whole string through to detect "StartsWith", but as I'm not familiar of the initial developer intention, I rather just returned that line to the previous implementation.