refactor(ninjafile): simplify ninja.kak and fix few things
refactor(ninjafile): simplify ninja.kak and fix few things

* fix multilines for declarations
* fix names with `-`, which Ninja allows
* fix few cases of `=` operators
* fix reserved keywords in `command = …` right-hand side

Co-authored-by: Frank LENORMAND <f27e221fc6ad108dd64ca540ee4bd76400db907e@users.noreply.github.com>

danr/kakoune,Somasis/kakoune,casimir/kakoune,casimir/kakoune,jkonecny12/kakoune,alexherbo2/kakoune,alexherbo2/kakoune,mawww/kakoune,danr/kakoune,danr/kakoune,casimir/kakoune,Somasis/kakoune,lenormf/kakoune,casimir/kakoune,Somasis/kakoune,lenormf/kakoune,lenormf/kakoune,alexherbo2/kakoune,alexherbo2/kakoune,danr/kakoune,Somasis/kakoune,mawww/kakoune,lenormf/kakoune,mawww/kakoune,jkonecny12/kakoune,jkonecny12/kakoune,jkonecny12/kakoune,mawww/kakoune