[Bug]: Missing whitespace in _axes.py error message #30285

Bug summary

In this code from _axes.py:

We see that the error message has been split into two lines, however it is missing a whitespace, resulting in the following typo:

argument must be a valid color orsequence of colors.

I would be very happy to tackle this myself as my first matplotlib PR if that's agreeable!

Code for reproduction

import matplotlib.pyplot as plt

# Create a simple plot
fig, ax = plt.subplots()

# This will trigger the facecolor error by passing an invalid color
ax.bar([1, 2, 3], [1, 2, 3], facecolor='invalid_color')

plt.show()

Actual outcome

ValueError: 'facecolor' or 'color' argument must be a valid color orsequence of colors.

Expected outcome

ValueError: 'facecolor' or 'color' argument must be a valid color or sequence of colors.

Additional information

No response

Operating system

No response

Matplotlib Version

3.10.0

Matplotlib Backend

No response

Python version

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Jupyter version

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Installation

None