Use -R instead of -r for fallback pager command

[mrsdizzie]

Not all versions of less offer -r as seen in #5758

Also, modern versions of LESS have the following warning when viewing man pages:

From man less

USE OF THE -r OPTION IS NOT RECOMMENDED.

-R or --RAW-CONTROL-CHARS is defined as:

 Like -r, but only ANSI "color" escape sequences and OSC 8 hyperlink sequences are output in "raw" form.

Reference: https://man7.org/linux/man-pages/man1/less.1.html

Fixes #5758

[danielbachhuber]

Do you know (or can you track down) when -R was introduced?

I have a slight backwards compat concern with this change, although it wouldn't be a huge detail because wp help is user-initated. I would feel more comfortable if we knew when -R was introduced, and which version of less was included on some major distros.

[mrsdizzie]

According to git blame of https://github.com/gwsw/less/blame/f229eab7eda5f31670b9ac2dd327fb148765e420/less.nro.VER#L979 it was around 17 years ago : )

[mrsdizzie]

Out of interest was able to track it back to https://www.greenwoodsoftware.com/less/news.346.html so it is available as of 5 Nov 1999:
New option -R (--RAW-CONTROL-CHARS) is like -r but handles long (wrapped) lines correctly, as long as the input contains only normal text and ANSI color escape sequences.

[danielbachhuber]

@mrsdizzie Great, thanks for doing that discovery.

It looks like there wasn't any discussion around less -r vs. less -R in the original pull request (#552), so I think it's fine to make the switch.