bug#66676: 29.1; Should some aspects of shr rendering be configurable

[Rahguzar]

Please note that there is bug in `shr--inline-image-p` defined in one of
the patches. Fixing it amounts too:

       (unless (integerp max-width)
        (setq max-width (* max-width (window-width nil t))))
       (unless (integerp max-height)
-       (setq max-width (* max-width (frame-char-height))))
+       (setq max-height (* max-height (frame-char-height))))
       (and (< (car size) max-width)
-          (< (cdr size) max-width)))))
+          (< (cdr size) max-height)))))

I will add it to the next revision of the patch along with any other
changes due to feedback.

Thanks,
Rahguzar