Add approximate attr to outputs

[mattansb]

See easystats/report#184

Set to FALSE unless passes to effectsize.htest()

• effectsize.BFBayesFactor()
• cohens_d() hedges_g() glass_delta()
• phi() cohens_w() cramers_v() oddsratio() riskratio() cohens_h() cohens_g()
• rank_biserial() cliffs_delta() rank_epsilon_squared() kendalls_w()

Depends...

• effectsize.htest() - depends on data recovery
• eta_squared() omega_squared() epsilon_squared() cohens_f() cohens_f_squared() - depends on true SS use

@IndrajeetPatil The "From Test Statistics" functions (F/z/t/chisq_to_*) won't get this attribute, because there's no way to know where the input is from.
And the "Between Effect Sizes" function also wont get, because these function only return single numerics.
(Same for standardize_parameters() - I think it is meaningless there anyway).

How does that sound?

[IndrajeetPatil]

All of that sounds good to me! Thanks.

[mattansb]

Closing in favor of #348