Summary
This PR adds support for bubble plots to ImPlot, inspired by MATLAB’s bubblechart. Existing plot functionality is unaffected.

Function signatures

IMPLOT_TMP void PlotBubbles(const char* label_id, const T* values, const T* szs, int count, double xscale=1, double xstart=0, ImPlotBubblesFlags flags=0, float min_pxsize=3, float max_pxsize=50, int offset=0, int stride=sizeof(T));
IMPLOT_TMP void PlotBubbles(const char* label_id, const T* xs, const T* ys, const T* szs, int count, ImPlotBubblesFlags flags=0, float min_pxsize=3, float max_pxsize=50, int offset=0, int stride=sizeof(T));
IMPLOT_API void PlotBubblesG(const char* label_id, ImPlotGetter3D getter, void* data, int count, ImPlotBubblesFlags flags=0, float min_pxsize=3, float max_pxsize=50);

• min_pxsize and max_pxsize set the minimum and maximum bubble diameters (in pixels).
• By default, marker outlines are not rendered and the fill color alpha is set to 0.5.

Example
Below is an example bubble plot (two different datasets). The bubble sizes are scaled between the specified min_pxsize and max_pxsize ([3, 50] for blue and [5, 20] for orange):

image

Feedback
Please let me know if there are any suggestions or improvements regarding:

• The API signature or naming.
• Default styling choices (e.g., alpha, line rendering).
• Performance or edge-case handling.

I appreciate any comments or reviews on how to refine this feature!