PR summary

This PR fixes minor documentation inconsistencies shared by both pcolor and pcolormesh.

• Incompatible X, Y, and C raise a TypeError rather than ValueError.
• For shading='flat' when X, Y and C have the same shape as C, the last row/column of C is no longer dropped with a deprecation warning

The pcolormesh documentation fix already appears in #31362, but I noticed the same issue in pcolor as well, so I'm opening this separate PR to address both.

Example

>>> import numpy as np
>>> import matplotlib.pyplot as plt
>>> fig, ax = plt.subplots()
>>> nrows, ncols = 2, 3
>>> C = np.arange(nrows * ncols).reshape(nrows, ncols)
>>> x, y = np.arange(ncols + 1), np.arange(nrows + 1)

Using pcolor with shading='nearest' with incompatible X, Y and C:

>>> ax.pcolor(x, y, C, shading='nearest')
...
TypeError: Dimensions of C (2, 3) are incompatible with X (4) and/or Y (3); see help(pcolor)

Using pcolormesh with shading='flat' and X, Y having the same shape as C:

>>> ax.pcolormesh(x[:-1], y[:-1], C, shading='flat')
...
TypeError: Dimensions of C (2, 3) should be one smaller than X(3) and Y(2) while using shading='flat' see help(pcolormesh)

AI Disclosure

None.

PR checklist

• [N/A] "closes #0000" is in the body of the PR description to link the related issue
• [N/A] new and changed code is tested
• [N/A] Plotting related features are demonstrated in an example
• [N/A] New Features and API Changes are noted with a directive and release note
• Documentation complies with general and docstring guidelines