5.1.1
fix(migrator): fix help message
fix(filter/highlight): avoid escaping curly bracket when highlight & prismjs are disabled (#4489)
refactor: simplify code (#4138)
fix(helpers): call url_for from hexo-util
feat(extend/injector): bring up new extend Injector (#4049)
chore(deps): update hexo-front-matter from 1.0.0 to 2.0.0 (#4439)
refactor(nunjucks): dedicated nunjucks renderer (#4356)
feat(highlight): parse 'caption' option to prismHighlight