Add guidance on making documentation SVG images responsive
Recently added guidance on adding SVG images to the documentation
sources lacks advice on making the images responsive when rendered
in a variety of media types and viewports. Add some.
Patch by Jonathan Katz with some editorialization by me.
Author: Jonathan Katz
Discussion: https://postgr.es/m/
6358ae6f-7191-a02b-e7b5-
68050636ae71@postgresql.org