Links into code base should be changed to links to API docs

[jobara]

Some of the documentation's references to particular functions are currently links directly into the code base for that function. We now have many functions documented (http://docs.fluidproject.org/infusion/development/CoreAPI.html) so we should go through the docs and cross-check any of these references. If there is documentation, link to it. If there is not, consider adding some?

Additional context or notes

Originally filed as FLUID-5839 by @acheetham on January 8, 2016.