Is your feature request related to a problem? Please describe.
I'm always frustrated when I want to sort some column other than the most common ones like name or age. I have to check the help with ? to see what sort is available. And most time they are not available. for example the claim field in persistentvolume

Describe the solution you'd like
k9s may adopt the solution in top where

Sorting the top output
By default, top sorts its entries by the CPU usage. You can change that by pressing M to sort by memory usage. To reverse sort your output, press R. To return to sorting by CPU, press P. To sort by other fields press < to move the sort column to the left and > to move the sort column to the right. To get help, press h. To exit top, press q.

So that would be: we can keep the current shortcut
but also provide any column sort by.

• press < to move the sort column to the left
• press > to move the sort column to the right.
• press R to reverse sort