Problem

#28073 added support for arrays on edgecolor, facecolor, linewidth, linestyle, hatch.

#28873 noted that we do not support the arrays for the aliases ec, fc, ... We also do not support plural versions of these parameters edgecolors, facecolors, ...

This is a reasonable expectation.

Proposed solution

• Alias support should be added.
• I believe we should come up with a clearer general strategy on singular/plural versions of the kwargs. Some initial thoughts:
  • Make a survey of which functions already support array properties and via which APIs.
  • the singular versions exist as pass-through. They need to be supported anyway. We could (i) only accept singular values there or (ii) also accept sequences. (ii) seems the more user-friendly approach and is implemented in some APIs already.
  • if we support plurals, we need to internally merge the single and plural variants, same with aliases. We likely should make helper functions for this. Can aliases be reused?