fdo#57950: Replace some chained appends in sw

Change-Id: Ie49834e8178c75ee7d69c556f7b7005b76e57498
Reviewed-on: https://gerrit.libreoffice.org/8607
Reviewed-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
Tested-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>