www/elinks: update to 0.15.1

ChangeLog: https://github.com/rkd77/elinks/releases/tag/v0.15.1

 * about:config
 * option --always-load-config
 * compilation fixes on Windows
 * added ui.background_char
 * sample build scripts and docker files
 * experimental DGI support
 * DOS port based on links code
 * configurable Accept-Header
 * minor compilation fixes

PR:		266305
Reported by:	jailbird@fdf.net (maintainer)