feat: add DEFAULT_MERGE_STYLE to repository.pull-request section for repo init (#19751)

custom/conf/app.example.ini

@@ -948,6 +948,9 @@ PATH =
 ;; List of keywords used in Pull Request comments to automatically reopen a related issue
 ;REOPEN_KEYWORDS = reopen,reopens,reopened
 ;;
+;; Set default merge style for repository creating, valid options: merge, rebase, rebase-merge, squash
+;DEFAULT_MERGE_STYLE = merge
+;;
 ;; In the default merge message for squash commits include at most this many commits
 ;DEFAULT_MERGE_MESSAGE_COMMITS_LIMIT = 50
 ;;