feat: Remove warning about SVG width and height (#1225)

This warning annoys a lot of people unnecessarily.

The argument that this means that the diagram doesn't stretch is true
(it won't stretch), but misleading, because stretching is not a good
goal to seek.  Diagrams in RFCs often have text, which either becomes too large
or too small when stretched.  Consequently, the right choice is to set
width and height in many cases.

Indeed, the example in RFC 7992 includes width and height (and no
viewbox, but that's a separate issue).  RFC 7996 does nothing about
this.  This warning is therefore overreach.

Author: martinthomson

Diff for: xml2rfc/writers/html.py

@@ -916,8 +916,6 @@ def render_artwork(self, h, x):
             vbox = svg.get('viewBox')
             svgw = maybefloat(svg.get('width'))
             svgh = maybefloat(svg.get('height'))
-            if svgw or svgh:
-                self.warn(x, "Found SVG with width or height specified, which will make the artwork not scale.  Specify a viewBox only to let the artwork scale.")
             try:
                 if vbox:
                     xo,yo,w,h = re.split(',? +', vbox.strip('()'))
@@ -926,12 +924,11 @@ def render_artwork(self, h, x):
                     if not (svgw and svgh):
                         svgw = float(w)-float(xo)
                         svgh = float(h)-float(yo)
+                elif svgw and svgh:
+                    svg.set('viewBox', '0 0 %s %s' % (svgw, svgh))
                 else:
-                    if svgw and svgh:
-                        svg.set('viewBox', '0 0 %s %s' % (svgw, svgh))
-                    else:
-                        self.err(x, "Cannot place SVG properly when neither viewBox nor width and height is available") 
-                        return None
+                    self.err(x, "Cannot place SVG properly when neither viewBox nor width and height is available")
+                    return None
             except ValueError as e:
                 self.err(x, "Error when calculating SVG size: %s" % e)
             imgw = 660 if self.options.image_svg else 724