Rewrite $REVERSE_SOLIDUS to %2F

Since on Unix we used to have $REVERSE_SOLIDUS but no longer do.
Also get URL's with only one $COLON rewriting properly.

Author: samcv

html/.htaccess

@@ -11,6 +11,8 @@ RewriteRule ^(.*)$ https://docs.perl6.org/$1 [R=permanent,L]
 # in case someone is using the long and awful URLs
 # RewriteRule ^type/(.*?)::(.*) /type/$1\$COLON\$COLON$2 [N]
 RewriteRule ^type/(.*?)\$COLON\$COLON(.*) /type/$1::$2 [N]
+RewriteRule ^type/(.*?)\$COLON(.*) /type/$1::$2 [N]
+RewriteRule ^type/(.*?)\$REVERSE_SOLIDUS(.*) /type/$1%5c$2 [N]
 
 Redirect 301 /language/5to6 https://docs.perl6.org/language/5to6-nutshell
 Redirect 301 /examples      http://examples.perl6.org/