Python Forum

Is there a generally recommended standard for Python application documentation? I'm discovering reStructured Text and Sphinx but I'd like to know if that's commonplace and if not, is there a widely recommend doc ecosystem?

There is a general guideline at python.org here.
I crank out code quickly, most documentation, except for very complicated methods, I keep in a separate document.
I do, often, add one liners at the beginning of a method, but only when coding at a relaxed pace, which is rarely the case.

Let me point out that the guideline linked by @Larz60+ is intended for the documentation of the Python language itself. It is not meant for people writing external Python libraries. Other guides exist, such as this one

The best libraries in the Python Package Index use Sphinx for their documentation and they often publish it on the readthedoc site.