Swap Next/Prev for time-based ordering to match Obsidian

[brendon-felix]

My changes intentionally alter the behavior of creation time and modified time ordering since I believe they are backwards. This breaks the tests that failed in #17.

In Obsidian's file explorer, the normal ordering for created time and modified time is 'new to old' with reverse ordering being 'old to new'. In my opinion, the next/prev file commands should match the file explorer ordering. Users can always swap the hotkeys for next/prev if they would like to.

Originally posted by @brendon-felix in #17 (comment)

[FabianUntermoser]

Good find! I agree.

What do you think about naming the commands in a more helpful way, such as navigate to newer file for sorting based on the modification timestamp?

[brendon-felix]

I do think that would make the commands more clear, especially with #17 merged. My understanding is that "Navigate to prev file (creation timestamp)" would be replaced with with "Navigate to newer file (creation timestamp)" and "Navigate to next file (creation timestamp)" would be replaced with with "Navigate to older file (creation timestamp)" and so on.

[FabianUntermoser]

Hey @brendon-felix, have a look at #21 to see if were on the same page. LGTM.