Change output format of `repo:changelog` task (#31546)

lib/tasks/repo.rake

@@ -49,8 +49,11 @@ namespace :repo do
       File.open(path, 'r') do |file|
         file.each_line do |line|
           if line.start_with?('-')
-            new_line = line.gsub(/[(]#([[:digit:]]+)[)]\Z/) do |pull_request_reference|
-              pull_request_number = pull_request_reference[2..-2]
+            new_line = line.gsub(/\(#([[:digit:]]+)(, #([[:digit:]]+))*\)\Z/) do |pull_requests_string|
+              pull_requests = pull_requests_string[1...-1].split(',').map { |pr_id| pr_id.strip[1...] }
+              response = nil
+
+              authors = pull_requests.map do |pull_request_number|
                 response = nil
 
                 loop do
@@ -66,7 +69,12 @@ namespace :repo do
                 end
 
                 pull_request = Oj.load(response.to_s)
-              "([#{pull_request['user']['login']}](#{pull_request['html_url']}))"
+                pull_request['user']['login']
+              end
+
+              authors.sort!.uniq!
+
+              "(#{pull_requests.map { |pr| "##{pr}" }.to_sentence} by #{authors.map { |author| "@#{author}" }.to_sentence})"
             end
 
             tmp.puts new_line