Add missing page references on testing index (#2224)
Add missing page references on testing index (#2224)

* Add missing page references

[This page](https://guides.emberjs.com/v2.18.0/testing/#toc_container-tests) contained broken links for "Testing Routes" and "Testing Controllers"

* fix relative markdown paths that I missed during merge

tleskin/guides,tleskin/guides,tleskin/guides