* Change favicon format from ICO to PNG
* Revert renaming `./favicon.ico`
Keep the backwards compatible file name `./favicon.ico` (though they will actually be in PNG format now).
* Add SVG template for creating favicons
Add `favicons.svg`, the template for creating the current PNG favicons, along with some helpful information about it in `favicons.svg.md`.
* Add source Inkscape SVG
Add source Inkscape SVG as an example of image tiddler in tw-com
* Enable the internals plugin by default in docs
1. Why hide such a useful thing from the users?
2. When playing around with code examples from the docs they may want to know how the resulting html looks.
* Improve doc
* Typo
Co-authored-by: Jeremy Ruston <jeremy@jermolene.com>
