Refactor: Rename helper function for consistency

[Haisom]

Description of Changes

• Renamed 'IsMemoryCardFolder' to 'FileMcd_IsFolder' for better consistency and clarity on MemoryCardFile.cpp.

Rationale behind Changes

• Consistency and clarity

Suggested Testing Steps

• Not needed

[RedDevilus]

Isn't FileMCD the variable and the helper function more on regular English?

Not sure if that is better, and are you referring to consistency with other places?

[Haisom]

Every function inside MemoryCardFile.cpp is named "FileMcd_", so I thought it would also apply for that.
But if a helper function is intended to be named like regular english then this should be just ignored and closed.

[RedPanda4552]

I'll leave this for others to decide, but the reason names are all over the place here is because memory card code is all over the place. The code is organized in this weird way where MemoryCardFile ends up being both the implementation of a file memory card, as well as the abstraction layer for all memory cards. MemoryCardFolder then is just the implementation of a folder memory card. So when something needs a different implementation it needs to be made in both sources, but if not then it can just go in MemoryCardFile. But the abstraction layer functions (at least many of them) still start with FileMcd because, well no one knows really, as far as I know at least.

[Haisom]

I'll leave this for others to decide, but the reason names are all over the place here is because memory card code is all over the place. The code is organized in this weird way where MemoryCardFile ends up being both the implementation of a file memory card, as well as the abstraction layer for all memory cards. MemoryCardFolder then is just the implementation of a folder memory card. So when something needs a different implementation it needs to be made in both sources, but if not then it can just go in MemoryCardFile. But the abstraction layer functions (at least many of them) still start with FileMcd because, well no one knows really, as far as I know at least.

Well, in case it helps, I tried looking for it in whole solution and there were only 3 references.

However, if it's true that helper functions should be named as it is, then no change is needed and I should update the one I PRed for the memory cards swapping from 'FileMcd_IsAutoEjecting' to 'IsMemoryCardAutoEjecting'.