Feature Request: Allow for annotations of coordinates in simplekml.LineString

It would be really great to be able to add information along the coordinates of a line string, and have those as annotations along the line, eg.:

```
import simplekml
kml = simplekml.Kml()
ls = kml.newlinestring(name='A LineString')
ls.coords = [(18.333868,-34.038274,10.0, f"Heading: {heading}\nSpeed: {speed}")]
```