feat: `gt_plt_point()`

[juleswg23]

Create a point plot in place of each value.

• function
• test
• docstring
• import to init
• quartodoc

[juleswg23]

Consider how this interacts with gt_plt_percentile()

https://jthomasmock.github.io/gtExtras/reference/gt_plt_percentile.html