resolved fdo#41166 match month and day name word instead of substring

(cherry picked from commit 8e71f81f47c20320c4de7a7aadb7d524f0d8ea76)
(cherry picked from commit 3885b5d4b00ebb31adabc36c507abd642c03d0d4)

Change-Id: I897dbcee47de574d91ba3e3b40a39a35b779fef8
Reviewed-on: https://gerrit.libreoffice.org/9387
Reviewed-by: Kohei Yoshida <libreoffice@kohei.us>
Tested-by: Kohei Yoshida <libreoffice@kohei.us>