Added documentation for discontinuous functions

[icedcoffeeee]

Overview: What does this pull request change?

• Added documentation for the parameters discontinuities and dt
• Added an example of how to better portray discontinuous functions

Motivation and Explanation: Why and how do your changes improve the library?

The example added:

class DiscontinousExample(Scene):
    def construct(self):
        ax1 = NumberPlane((-3, 3), (-4, 4))
        ax2 = NumberPlane((-3, 3), (-4, 4))
        VGroup(ax1, ax2).arrange()
        discontinuous_function = lambda x: (x ** 2 - 2) / (x ** 2 - 4)
        before = ax1.plot(discontinuous_function, color=RED)
        after = ax2.plot(
            discontinuous_function,
            discontinuities=[-2, 2],  # discontinuous points
            dt=0.1,  # left and right tolerance of discontinuity
            color=GREEN,
        )
        self.add(ax1, ax2, before, after)

Outcome:

Links to added or changed documentation pages

Documentation

Further Information and Comments

Reviewer Checklist

• The PR title is descriptive enough for the changelog, and the PR is labeled correctly
• If applicable: newly added non-private functions and classes have a docstring including a short summary and a PARAMETERS section
• If applicable: newly added functions and classes are tested

[Darylgolden]

Can you fix the docs build and merge conflict?

[Darylgolden]

Minor comment about phrasing, otherwise LGTM

[Darylgolden]

I think this wording is a little strange. How about "If your function has discontinuities, you'll have to specify the location of the discontinuities manually. See the following example for guidance."

[behackl]

LGTM!

[Darylgolden]

I think it'll be good to call "before" and "after" "incorrect" and "correct" instead.

Variable names have been changed.