update description of the Special Characters dialog

Change-Id: I76c2839804ebbf4d1be825a31d09c2566f0e714c
Reviewed-on: https://gerrit.libreoffice.org/12138
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
rename Fields - Other to Fields - More Fields

Change-Id: I7460acb296b32c99c37a77bbce05d44aa3f36bd7
Reviewed-on: https://gerrit.libreoffice.org/12140
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>