AK: Fix missing step step for serialization of IPv6 hosts

This was resulting in the incorrect host serialization of:

http://[0:1:0:1:0:1:0:1] to [::1:0:1:0:1:0:1]

and:

http://[1:0:1:0:1:0:1:0] to [1::1:0:1:0:1:0]

AK/URLParser.cpp

@@ -232,7 +232,6 @@ static void serialize_ipv6_address(URL::IPv6Address const& address, StringBuilde
     // 1. Let output be the empty string.
 
     // 2. Let compress be an index to the first IPv6 piece in the first longest sequences of address’s IPv6 pieces that are 0.
-    // 3. If there is no sequence of address’s IPv6 pieces that are 0 that is longer than 1, then set compress to null.
     Optional<size_t> compress;
     size_t longest_sequence_length = 0;
     size_t current_sequence_length = 0;
@@ -250,6 +249,11 @@ static void serialize_ipv6_address(URL::IPv6Address const& address, StringBuilde
             current_sequence_length = 0;
         }
     }
+
+    // 3. If there is no sequence of address’s IPv6 pieces that are 0 that is longer than 1, then set compress to null.
+    if (longest_sequence_length <= 1)
+        compress = {};
+
     // 4. Let ignore0 be false.
     auto ignore0 = false;
 

Tests/LibWeb/Text/expected/URL/url.txt

@@ -7,3 +7,21 @@ hostname => 'serenityos.org'
 port => ''
 pathname => '/'
 search => ''
+http://[0:1:0:1:0:1:0:1]
+protocol => 'http:'
+username => ''
+password => ''
+host => '[0:1:0:1:0:1:0:1]'
+hostname => '[0:1:0:1:0:1:0:1]'
+port => ''
+pathname => '/'
+search => ''
+http://[1:0:1:0:1:0:1:0]
+protocol => 'http:'
+username => ''
+password => ''
+host => '[1:0:1:0:1:0:1:0]'
+hostname => '[1:0:1:0:1:0:1:0]'
+port => ''
+pathname => '/'
+search => ''

Tests/LibWeb/Text/input/URL/url.html

@@ -16,6 +16,8 @@
 
         for (url of [
             'ftp://serenityos.org:21',
+            'http://[0:1:0:1:0:1:0:1]',
+            'http://[1:0:1:0:1:0:1:0]',
         ]) {
             printURL(url);
         }