checkpatch: allow Closes tags with links

As a follow-up of a previous patch modifying the documentation to
allow using the "Closes:" tag, checkpatch.pl is updated accordingly.

checkpatch.pl now no longer complain when the "Closes:" tag is used by
itself:

  commit 76f381b ("checkpatch: warn when unknown tags are used for links")

... or after the "Reported-by:" tag:

  commit d7f1d71 ("checkpatch: warn when Reported-by: is not followed by Link:")

Closes: multipath-tcp/mptcp_net-next#373
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>

scripts/checkpatch.pl

@@ -620,7 +620,7 @@ sub hash_show_words {
 	Cc:
 )};
 
-our @link_tags = qw(Link);
+our @link_tags = qw(Link Closes);
 
 #Create a search and print patterns for all these strings to be used directly below
 our $link_tags_search = "";
@@ -3174,14 +3174,14 @@ sub process {
 				}
 			}
 
-# check if Reported-by: is followed by a Link:
+# check if Reported-by: is followed by a Closes: tag
 			if ($sign_off =~ /^reported(?:|-and-tested)-by:$/i) {
 				if (!defined $lines[$linenr]) {
 					WARN("BAD_REPORTED_BY_LINK",
-					     "Reported-by: should be immediately followed by Link: with a URL to the report\n" . $herecurr . "\n");
-				} elsif ($rawlines[$linenr] !~ m{^link:\s*https?://}i) {
+					     "Reported-by: should be immediately followed by Closes: with a URL to the report\n" . $herecurr . "\n");
+				} elsif ($rawlines[$linenr] !~ m{^closes:\s*https?://}i) {
 					WARN("BAD_REPORTED_BY_LINK",
-					     "Reported-by: should be immediately followed by Link: with a URL to the report\n" . $herecurr . $rawlines[$linenr] . "\n");
+					     "Reported-by: should be immediately followed by Closes: with a URL to the report\n" . $herecurr . $rawlines[$linenr] . "\n");
 				}
 			}
 		}