amendment for figure titles in datetimes

[tiozab]

r4ds/datetimes.qmd

Line 223 in 495dc85

With this data, we can visualize the distribution of departure times across the year:

the figure title confused me and I think it would be clearer to say :
With this data, we can visualize the number of departures per day across the year.

And then the title for the following figure

r4ds/datetimes.qmd

Line 239 in 495dc85

Or within a single day:

the sentence would be clearer as follows:
Or per 10 minutes across one day.