Docs: Missing warning about path_helper

[robjwells]

How can we improve the documentation?

In the Getting Started guide there is a note to macOS users to read a warning about path_helper:

macOS users, be sure to read the warning about path_helper at the end of this section.

But there is no further mention of path_helper on that page. There is, however, a warning about path_helper in the pre-0.16 Getting Started guide.

Does this warning still apply?