DOC: fix a typo: "RBG" -> "RGB" (#50138)

Author: partev

pandas/plotting/_misc.py

@@ -293,7 +293,7 @@ def andrews_curves(
         Number of points to plot in each curve.
     color : str, list[str] or tuple[str], optional
         Colors to use for the different classes. Colors can be strings
-        or 3-element floating point RBG values.
+        or 3-element floating point RGB values.
     colormap : str or matplotlib colormap object, default None
         Colormap to select colors from. If a string, load colormap with that
         name from matplotlib.