Prefer directed to neutral quotes

Prefer directed to neutral quotes

Prefer directed to neutral quotes in docstings and diagnostics.
In docstrings, escape apostrophes that would otherwise be translated
to curved quotes using the newer, simpler rules.

* auth-source.el (auth-source-netrc-parse-entries):
* gnus-agent.el (gnus-agent-check-overview-buffer)
(gnus-agent-fetch-headers):
* gnus-int.el (gnus-start-news-server):
* gnus-registry.el (gnus-registry--split-fancy-with-parent-internal):
* gnus-score.el (gnus-summary-increase-score):
* gnus-start.el (gnus-convert-old-newsrc):
* gnus-topic.el (gnus-topic-rename):
* legacy-gnus-agent.el (gnus-agent-unlist-expire-days):
* nnmairix.el (nnmairix-widget-create-query):
* spam.el (spam-check-blackholes):
Use directed rather than neutral quotes in diagnostics.