look for OUStringBuffer append sequences that can be turned
into creating an OUString with + operations
Change-Id: Ica840dc096000307b4a105fb4d9ec7588a15ade6
Reviewed-on: https://gerrit.libreoffice.org/80809
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>