[Rd] New URL redirect checks

[Gábor Csárdi]

Dear all,

the new CRAN URL checks flag HTTP 301 redirects. While I understand
the intent, I think this is unfortunate, because several URL shortener
services use 301 redirects, and often a shorter URL is actually better
in a manual page than a longer one that can be several lines long in
the console and also potentially truncated in the PDF manual.

Some example shorteners that are flagged:

> db <- tools:::url_db(c("https://nyti.ms", "https://t.co/mtXLLfYOYE"), "README")
> tools:::check_url_db(db)
URL: https://nyti.ms (moved to https://www.nytimes.com/)
From: README
Status: 200
Message: OK

URL: https://t.co/mtXLLfYOYE (moved to
https://www.bbc.co.uk/news/blogs-trending-47975564)
From: README
Status: 200
Message: OK