Use -R instead of -r for fallback pager command by mrsdizzie · Pull Request #5759

Use -R instead of -r for fallback pager command by mrsdizzie · Pull Request #5759 · wp-cli/wp-cli

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

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

"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.

Fixes wp-cli#5758