extend autoplot.sim_results()

[d-morrison]

This pull request enhances the flexibility and usability of the autoplot.sim_results function by allowing users to customize which columns are mapped to the x-axis, group, and color aesthetics in plots. The documentation has been updated to reflect these new options.

Function enhancements:

• Added new parameters to autoplot.sim_results: x_var, group_var, and color_var, allowing users to specify which columns in the input data frame are used for the x-axis, group, and color aesthetics in the plot.
• Updated the function to use the values of x_var, group_var, and color_var when constructing the plot, replacing hardcoded column references.

Documentation updates:

• Revised the Rd documentation for autoplot.sim_results to describe the new parameters and clarify the expected input format.

[d-morrison]

@copilot update the changelog

[Copilot]

@d-morrison I've opened a new pull request, #463, to work on those changes. Once the pull request is ready, I'll request review from you.

[github-actions]

📖 https://UCD-SERG.github.io/serocalculator/preview/pr462/
Preview documentation for this PR (at commit d287e13)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

Files with missing lines	Coverage Δ
R/autoplot.sim_results.R	100.00% <100.00%> (ø)