Documentation about antialiased lines

There should be an explicit section or page of the project documentation to explain antialiased lines. There is some mention of this in the timeseries page of the user guide.

Start with the timeseries page in the user guide, where antialiased lines are already mentioned. Trace the surrounding documentation structure to choose an appropriate section or page, then document antialiased lines clearly; the work is done when the topic has an explicit, discoverable explanation in the user guide.

Written by the indexing model from the issue text.