Pcolormesh Doc Fix (matplotlib#30912)

---------

Co-authored-by: Tim Hoffmann <2836374+timhoffm@users.noreply.github.com>

Author: sanrishi

lib/matplotlib/axes/_axes.py

@@ -6805,9 +6805,12 @@ def pcolormesh(self, *args, alpha=None, norm=None, cmap=None, vmin=None,
             See :doc:`/gallery/images_contours_and_fields/pcolormesh_grids`
             for more description.
 
-        snap : bool, default: False
+        snap : bool, default: :rc:`pcolormesh.snap`
             Whether to snap the mesh to pixel boundaries.
 
+            .. versionchanged:: 3.4.0
+               The default value changed from *False* to *True* to improve transparency
+               handling. See :ref:`whats-new-3-4-0` for details.
         rasterized : bool, optional
             Rasterize the pcolormesh when drawing vector graphics.  This can
             speed up rendering and produce smaller files for large data sets.