Split backported and non-backported portions of #667 in changelog.
Split backported and non-backported portions of #667 in changelog.

internalfx/nunjucks,kevinschaul/nunjucks,oddbird/nunjucks,internalfx/nunjucks,internalfx/nunjucks,mozilla/nunjucks,mozilla/nunjucks,internalfx/nunjucks,devoidfury/nunjucks,mozilla/nunjucks,oddbird/nunjucks,kevinschaul/nunjucks,oddbird/nunjucks,kevinschaul/nunjucks,oddbird/nunjucks,kevinschaul/nunjucks,devoidfury/nunjucks,devoidfury/nunjucks