[features-] add command to hide repetitive columns

[midichef]

This is a command to hide any column that contains one value repeated in every row. Is this worth having? It's often the first command I run when opening large tables with such uninformative columns.

I'm not sure what to call the command. Right now it is hide-unvarying-cols, but perhaps hide-uniform-cols is better? hide-repetitive-cols is too hard to spell.

[frosencrantz]

This would be a useful command. Thank you for proposing it @midichef!

I like it and would use it. Saul provided a useful suggestion when I asked in Issue 431 (2022 issues ago):

[howto] hide invariant columns

[midichef]

I changed the command prefix to hide-uniform- instead f hide-unvarying-. One reason is, "unvarying" is hardly ever used as a technical term, so it would be a new word for users to to recall. Another is, "hide" and "un-varying" describe the result based on two negatives (the positive equivalents would be "show" and "varying"). "uniform" seems better as it describes the targets of "hide" in terms of what they are (uniform), instead of what they aren't (varying).

If there's a common word that means "having one distinct value", I'd like to know.

[saulpw]

I changed the command prefix to hide-uniform- instead f hide-unvarying-.

I was considering suggesting 'invariant' but I think I like uniform better (less formal). Thanks for giving it some thought.