Move "Syntax sugar", transform() methods

Move "Syntax sugar", transform() methods

The "Transforming elements" section has been renamed "Size and position".

The `transform()` method has been moved to the "Geometry" section.

The "Syntax sugar" section has been broken up and removed:
* `radius()` has been moved to "Size and position" (and has been edited for completeness and clarity)
* `fill()`, `stroke()`, and `opacity()` have been moved to "Attributes and styles"
* `rotate()`, `skew()`, `scale()`, and `translate()` have been grouped with `transform()` under "Geometry"