Add Signal contact link

src/contact.pug

@@ -15,6 +15,9 @@ block content
 		h2#hi Contact
 		p There are numerous ways to contact me:
 		ul
+			li
+				a(rel='me', href='https://signal.me/#eu/BRqzXtiClVB2hQJn4fZJyHzPeAxi_78Zz1QJEhwnLwxyd3FXDddHmIs4vSHHIvVp') Via Signal
+				|  (much preferred)
 			li
 				a(rel='me', href='https://matrix.to/#/@alex:strugee.net') Via Matrix
 				|  (much preferred)
@@ -23,7 +26,7 @@ block content
 			li On IRC (I am <code>strugee</code> on Libera.chat, GIMPNet, and OFTC, and <code>ajordan</code> on the W3C IRC servers, though I don't check IRC much anymore)
 			li
 				a(rel='me', href='mailto:alex@strugee.net') By email
-			li By SMS or preferably, Signal - number available upon request
+			li By SMS; number available upon request
 
 		p If you need to communicate with me securely, use Matrix (make sure you have encryption on) or Signal. I accept <a href="/gpg">GPG-encrypted mail</a> but would much prefer to use something else.