Less version 581

Version 581 was released on 7 Apr 2021. An upgraded version 581.2 was released on 28 Apr 2021.

These are the differences between version 563 and version 581:

• Change ESC-u command to toggle, not disable, highlighting per man page.
• Add ESC-U command.
• Add ctrl-W search modifier for wrapping search.
• F command can be interrupted by ^X.
• Support OSC 8 hyperlinks when -R is in effect.
• g command with no number will ignore -j and put first line at top of screen.
• Multiple + or -p command line options are handled better.
• Add the --incsearch option.
• Add the --line-num-width option.
• Add the --status-col-width option.
• Add the --use-color and --color options.
• Display -w highlight even if highlighted line is empty.
• If search result is in a long line, scroll to ensure it is visible.
• Editing the same file under different names now creates only one entry in the file list.
• Make visual bell more visible on some terminals.
• Ring end-of-file bell no more than once per second.
• Build can use either Python or Perl for Makefile.aut operations.
• Fix crash when using the @ search modifier.
• Fix crash in the 's' command due to duplicate free.
• Fix realpath crash on Darwin.