Fix typo in example config

[ChrisJefferson]

I might be using hexo / landscape wrong (I only just started), but I installed hexo and landscape, then copied the config from the readme into my _config.landscape.yml, and I got the following error (this is the important part of the error I think):

/home/caj/files/reps/websites/hexo-blog/nonbinaryalgorithms/node_modules/hexo-theme-landscape/layout/_partial/sidebar.ejs:3
    1| <aside id="sidebar"<% if (theme.sidebar === 'bottom'){ %> class="outer"<% } %>>
    2|   <% theme.widgets.forEach(function(widget){ %>
 >> 3|     <%- partial('_widget/' + widget) %>
    4|   <% }) %>
    5| </aside>

Partial _widget/archives does not exist. (in _partial/sidebar.ejs)

When I had a look, there is no _widget/archives, but there is _widget/archive, and when I fixed that the page could then be built, and I had a working archives link.

[stevenjoezhang]

See also

hexo-theme-landscape/_config.yml

Lines 29 to 34 in d615650

	widgets:
	- category
	- tag
	- tagcloud
	- archive
	- recent_posts