ruby.kak: support squiggly heredocs
ruby.kak: support squiggly heredocs

Squiggly heredocs were introduced in Ruby 2.3.

They work like `<<-` but strip indentation.
Somasis/kakoune,lenormf/kakoune,jkonecny12/kakoune,Somasis/kakoune,mawww/kakoune,jkonecny12/kakoune,jkonecny12/kakoune,jjthrash/kakoune,jjthrash/kakoune,danr/kakoune,lenormf/kakoune,Somasis/kakoune,alexherbo2/kakoune,mawww/kakoune,occivink/kakoune,danr/kakoune,Somasis/kakoune,occivink/kakoune,casimir/kakoune,mawww/kakoune,casimir/kakoune,alexherbo2/kakoune,lenormf/kakoune,casimir/kakoune,jkonecny12/kakoune,alexherbo2/kakoune,jjthrash/kakoune,mawww/kakoune,danr/kakoune,casimir/kakoune,jjthrash/kakoune,occivink/kakoune,alexherbo2/kakoune,occivink/kakoune,danr/kakoune,lenormf/kakoune