Hello!

A while back I turned off `shr-use-fonts' for my HTML email but found
that occasionally proportional fonts are useful when reading my
messages.

I am proposing the below `gnus-article-toggle-fonts' function with a
keybinding of `W D F'.

	New Gnus article washing option to toggle HTML fonts

	* lisp/gnus/gnus-sum.el (gnus-summary-wash-display-map): 
	(gnus-summary-make-menu-bar): Add mode mapping and menu item for
	article HTML font toggle.

	* lisp/gnus/gnus-art.el (gnus-article-toggle-fonts): Toggle
	shr-use-fonts and redisplay message.

	* doc/misc/gnus.texi (Article Washing): Document new HTML font
	toggle function.