Add __hash__ to ManimColor

[sophiawisdom]

Overview: What does this pull request change?

Adds a hash method to ManimColor

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

I wanted to use the Color in a dictionary and it didn't work and I thought other people might want the same.

Links to added or changed documentation pages

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

[chopan050]

ManimColor does not have a .copy() method. Maybe, instead of WHITE.copy(), the test could use ManimColor(WHITE), but this would only generate a reference to the same internal RGBA array in the current implementation. Another option is ManimColor([1.0, 1.0, 1.0, 1.0]), which represents the color white and generates a new RGBA array.

def test_color_hash():
    assert hash(WHITE) == hash(ManimColor([1.0, 1.0, 1.0, 1.0]))
    assert hash(WHITE) != hash(RED)

Because WHITE.to_hex(with_alpha=True) returns "#FFFFFFFF", you can also compare it directly with the hash of this string.

def test_color_hash():
    assert hash(WHITE) == hash("#FFFFFFFF")
    assert hash(WHITE) != hash(RED)