[Archive.is] Update ruleset (#5886)

* [Archive.is] Update ruleset

After having had a couple of different issues with this ruleset, cf. in particular

    #5805 and
    #4075

I prompted the webmaster for what would be a proper solution moving forwards. On their request, this avoids redirecting anything to https://archive.is/ but ensures that the relevant connections are still upgrading by using archive.fo instead.

* [Archive.is] Update comment

src/chrome/content/rules/Archive.is.xml

@@ -1,21 +1,27 @@
 <!--
-	Nonfunctional hosts in *archive.is:
+	Problematic domains:
+		- (www.)archive.is ¹
+		- blog.archive.is ²
 
-		- blog *
-
-	* tumblr
+	¹ By webmaster request, we avoid redirecting anything to https://archive.is/ but ensure that the relevant connections are still upgraded by using archive.fo instead.
+	² Mismatch
 -->
 <ruleset name="Archive.is (partial)">
 
 	<target host="archive.today" />
 	<target host="blog.archive.today" />
 	<target host="www.archive.today" />
+	<target host="archive.fo" />
+	<target host="www.archive.fo" />
 	<target host="archive.is" />
 	<target host="www.archive.is" />
 	<target host="archive.li" />
 	<target host="blog.archive.li" />
 	<target host="www.archive.li" />
 
+	<rule from="^http://(www\.)?archive\.is/"
+		to="https://$1archive.fo/" />
+
 	<rule from="^http:"
 		to="https:" />