Add value-pos to scale widget

[ipsvn]

Description

Adds value-pos to the scale widget, to change the position of where the value on the scale is shown

Usage

(scale
	:draw-value true
	:value-pos "right")

Additional Notes

If I have done anything wrong with the documentation stuff (e.g. the var comment on the parse function) please let me know.

Checklist

Please make sure you can check all the boxes that apply to this PR.

• All widgets I've added are correctly documented.
• I added my changes to CHANGELOG.md, if appropriate.
• The documentation in the docs/content/main directory has been adjusted to reflect my changes.
• I used cargo fmt to automatically format all code before committing