[why]
Codicons is completely missing...

[how]
After creating a stub file for Codicons, use _their_ definition file:

curl -O https://raw.githubusercontent.com/microsoft/vscode-codicons/main/dist/codicon.csv
cat codicon.csv | tail -n +2 | sort -k 3 -t ',' | sed -E "s/([^,]*),([^,]*),(.*)/i='\2' i_cod_\1=\$i/" | tr '-' '_' >> i_cod.sh

Because they have new additional icons remove some lines in the bottom.
And add the final `unset i`.

I still have not figured out how the cheat sheet works and how we get
the data into that... There is a `generate-css.sh`. Hmm.

Signed-off-by: Fini Jastrow <ulf.fini.jastrow@desy.de>

[why]
The file that would be created in temp/ is probably not needed
There is a lot out noise

[how]
Create the txt file only if we already have a temp/ dir.
Make that clear in the final output message.
Remove debugging outputs.

Signed-off-by: Fini Jastrow <ulf.fini.jastrow@desy.de>

[why]
The generated file `nerd-fonts-generated.css` is made smaller with an
external service as manual step...

  # [Nerd Fonts]  The following is generated from the build script, then through https://www.minifier.org/

We do not want any manual steps.

[how]
Luckily the difference is just to remove whitespaces and unneeded
semicoli. We can do the same while generating.

[note]
At first I tried to postprocess the generated file with sed, but of
course the strings that have blanks in them made that rather
complicated.

Signed-off-by: Fini Jastrow <ulf.fini.jastrow@desy.de>

Signed-off-by: Fini Jastrow <ulf.fini.jastrow@desy.de>

[why]
The add-and-commit steps are so unbelievable slow.

[how]
We do not need the other tags, so we do not need a fetch before adding.
See comments on the action's homepage.

Signed-off-by: Fini Jastrow <ulf.fini.jastrow@desy.de>