Commit 0893134543 (Added .editorconfig file (#3332) (#3313),
2016-08-25) trimmed trailing whitespace for Markdown file (which do
have significant trailing whitespace) but ReStructuredText does not,
and none of our Markdown files cares about this, so let's clean up
whitespace always.
* docs: Add "Writing your own prompt" doc
* Remove a space from the "output"
* some teensy adjustments
* Address feedback
* envvar one more PWD
* More html warning