Merge pull request #5325 from infosiftr/more-verbose-MAINTAINERS

Add a few comments to MAINTAINERS to make it more clear who these strange people are and what they maintain

MAINTAINERS

@@ -1,4 +1,9 @@
+# This file lists the maintainers of the Official Images program at large, not necessarily the maintainers of any given image.
+
 Tianon Gravi <[email protected]> (@tianon)
 Joseph Ferguson <[email protected]> (@yosifkit)
+
 # Emeritus: Talon Bowler <[email protected]> (@moghedrin)
 # Emeritus: Peter Salvatore <[email protected]> (@psftw)
+
+# To find the maintainers for a given image, see "library/IMAGENAME" in this repository, or see the "Maintained by:" section of the "Quick Reference" of the image description on Docker Hub (or in the "docs" repo at https://github.com/docker-library/docs).