Update the inkscape command:
- Remove `-C` as it is default for PDF now
- Replace the removed flag `-A` (`--export-pdf`) with `--export-filename`
- Remove `-f` as Inkscape now takes the file name directly
See: https://wiki.inkscape.org/wiki/index.php/Using_the_Command_Line#Deprecations_and_Replacements

Replace fonts:
- **Inconsolata LGC** to **Inconsolata**
- **Linux Libertine O** to **Libertinus Serif**
- **Linux Biolinum O** to **Libertinus Sans**

Arch suggests switching to **Libertinus**:

> Note: development of Libertine seems to have halted, despite outstanding bugs.
> Users are advised to upgrade to the de facto successor,
> [community]/libertinus-font, and to update any documents and configuration
> if necessary

After the word `Computer` there is a whitespace. With Inkscape 1,
that space is included in the line width when centering text, thus
results in the text line `of Computer` being shifted a little to the
left and doesn't look centered anymore.

Most figures use **Inconsolata**, but there are two figures using
**FreeMono**, **Courier New**, **Droid Sans Mono**, **Liberation Mono**
for lines (which I guess doesn't really care what font is used).
This commit makes them use **Inconsolata** too for consistency.

- Replace setext-style headings with atx ones.
- Add a new section for the fonts required to build.

This commit ports most fixes that are merged into the HTML repo but
haven't applied on this repo yet. Some overflowing code lines are
broken into smaller lines.

This is simpler than Git LFS.

Latin Modern is only used for the text inside 5 figures, so I replace it
with Inconsolata to reduce the number of fonts required for a build.

This commit also rebuild the PDF.