Missing archive_generator section in default _config.yml

[albertnetymk]

In the folder populated by hexo init, _config.yml doesn't contain archive_generator section, and the value of per_page variable on the root level is used instead.

per_page: 10
...
archive_generator:
  per_page: 0

[leesei]

The top level per_page is the default config for all generators:
https://github.com/hexojs/hexo-generator-archive/blob/master/index.js
https://github.com/hexojs/hexo-generator-category/blob/master/index.js
https://github.com/hexojs/hexo-generator-tag/blob/master/index.js