[Docs] Quickstart - Transform vs ReplacementTransform

[DegrangeM]

In the quickstart tutorial https://docs.manim.community/en/stable/tutorials/quickstart.html

The transform method is introduced : https://docs.manim.community/en/stable/tutorials/quickstart.html#transforming-a-square-into-a-circle

A little after, in Using .animate syntax to animate methods, the ReplacementTransform method is used.

It is confusing for new learner because they don't know why this new function is used instead of the other.

The docs should either :

• Only use the transform method (if possible)
• Only use the ReplacementTransform method (if possible)
• Keep using transform and ReplacementTransform but explain the new method

[bdotsamir]

This should be explained somewhere in the quickstart! This was a massive pain-point for me when I was learning Manim for the first time- I saw Transform used in 3b1b's videos and so that's what I used, but I was wondering why the design decision was to replace the original mobject with a reference to the transformed mobject. Caused headaches when I was trying to remember which variables held which Mobjects. ReplacementTransform solved this prayer.