Convert icons to PNG so that Safari will load them.

Conversion done with ImageMagick:
  convert -background none Ansible-Mark-RGB_Black.svg -resize 180x180 Ansible-Mark-RGB_Black.png
  convert -background none Ansible-Mark-RGB_White.svg -resize 180x180 Ansible-Mark-RGB_White.png

sphinx_ansible_theme/layout.html

@@ -4,13 +4,13 @@
 #}
 {%-
     set ansible_logo_url = logo_url
-        or ('_static/' + (logo or 'images/Ansible-Mark-RGB_White.svg'))
+        or ('_static/' + (logo or 'images/Ansible-Mark-RGB_White.png'))
 %}
 {%- set logo_url = '' %}{# Reset to prevent render in the RTD theme #}
 {%- set logo = logo_url %}
 {%-
     set favicon_url = favicon_url
-        or ('_static/' + (favicon or 'images/Ansible-Mark-RGB_Black.svg'))
+        or ('_static/' + (favicon or 'images/Ansible-Mark-RGB_Black.png'))
 %}
 {%- set favicon = favicon_url | replace('_static/', '', 1) %}
 {%- set favicon_url = pathto(favicon_url, 1) if '//' not in favicon_url and not favicon_url.startswith('/') else favicon_url %}