PR summary

• This PR is to address [Bug]: Missing axes limits auto-scaling support for LineCollection #29219, which addresses the missing auto-scaling support for LineCollection objects.
• The lack of this feature requires users to manually call ax.autoscale() when adding a LineCollection to an Axes.
• The PR adds the autoscale inside Axes.add_collection() function to ensure that the scaling is done automatically, without having to call ax.autoscale()

With the change, the following code:

from matplotlib.collections import LineCollection

lc = LineCollection([[(x, x ** 2) for x in range(5)]])
ax = plt.gca()
ax.add_collection(lc)
plt.show()

Successfully creates:

PR checklist

• "closes #0000" is in the body of the PR description to https://github.com/matplotlib/matplotlib/issues/29219
• new and changed code is tested
• Plotting related features are demonstrated in an example
• New Features and API Changes are noted with a directive and release note
• Documentation complies with general and docstring guidelines