PR summary

This PR by adding a:code-caption: option to the.. plot RST directive:

..plot:::include-source::code-caption: Simple line plot    import matplotlib.pyplot as plt    plt.plot([1, 2, 3], [1, 4, 9])    plt.xlabel('X axis')    plt.ylabel('Y axis')    plt.title('Simple Plot')

Closes#30740

PR checklist

• "closes #0000" is in the body of the PR description tolink the related issue
• new and changed code istested
• Plotting related features are demonstrated in anexample
• New Features andAPI Changes are noted with adirective and release note
• Documentation complies withgeneral anddocstring guidelines