create a tabulation mark properties setting object for Word
or RTF. Results can be used as arguments of fp_tabs().
Once tabulation marks settings are defined, tabulation marks can
be added with run_tab() inside a call to fpar() or
with \t within 'flextable' content.
See also
Other functions for defining formatting properties:
fp_border(),
fp_cell(),
fp_par(),
fp_tabs(),
fp_text()
