Describe your change:

• Documentation change?

Improve the docstring for graphics/digital_differential_analyzer_line.py as suggested in the issue:

• Added one-sentence principle: calculates dx/dy and iteratively steps along the dominant axis, incrementing the other by a fractional amount.
• Noted main disadvantage: reliance on floating-point arithmetic and rounding at every step.
• Mentioned it is generally outperformed by the Bresenham algorithm which uses integer-only math.
• Added Wikipedia reference: https://en.wikipedia.org/wiki/Digital_differential_analyzer_(graphics_algorithm)

Fixes #13905

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms have at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes Suggestion: Improve docstring for DDA algorithm #13905".

Fixes #13905