Consistently reference `theme_root_icon`

[mbudisic]

Removed explicit py.svg references in layout.html with theme_root_icon paths.

This pull request changes paths lines 17 and 103 to match line 74 in the base branch.

[cpython-cla-bot[bot]]

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[hugovk]

Good idea.

Although "Logo" isn't a great alt text, can we also add something like root_icon_alt_text to the config?

• https://webaim.org/techniques/alttext/#logos
• https://sc.edu/about/offices_and_divisions/digital-accessibility/toolbox/best_practices/alternative_text/logo-alt-text/index.php
• https://www.a11yproject.com/posts/alt-text/

[mbudisic]

Thank you for suggestions!