How to reformat the Highest Density Interval (HDI) result on the posterior plot from percentage to float

Question

I conducted a Bayesian mean difference test and obtained the posterior plot of the parameter estimation. I adjusted the HDI probability to 0.995; however, the plot_posterior function of Arviz rounds the probability value to 100% when displaying on the plot, as seen in the following figure. I need that plot to display 99.5%, which is the exact value of credible interval. Although the "round_to" argument allows controlling the formatting of floats, it didn't adjust the HDI percentage.