[tex4ht] New make4ht version and documentation

[Michal Hoftich]

Hi all,

I hope to release a new make4ht (and tex4ebook) versions soon. There
are some big news:

- I've updated the documentation. There is lot of new information,
fixed grammar, it has totally new structure. I still need to add one
final section about development of filters, extensions and output
formats.

- I've set up a Github action that compiles the documentation every
time I push an update and publishes it on my web:

https://www.kodymirus.cz/make4ht/make4ht-doc.html

I would be happy if anyone could take a look at it and find any errors
or things that are hard to understand. It has hypothes.is support, so
it is possible to add annotations directly on the web. We can also
chat on Matrix / Gitter:

https://matrix.to/#/!TPtwmiUBINdfBLVrmC:matrix.org
https://gitter.im/tex4ht/community?

One issue I found is that Debian's version of tex4ht contains some
wrong .htf files, because the code listings contains wrong characters
for {, } and some other chars.

- added support for reading of the input from the standard input. Just
use the "-" character instead of the filename

- I am considering reduction of the amount of the code written to the
terminal. I''ve setup LaTeX to use the batchmode and created parser
for detecting errors in the log file. The setting of the mode is
configurable, to return back to the original settings use

     filter_settings "htlatex" {interaction="errorstopmode"}

in a build file or  in the .make4ht configuration file. I've found
compilation in this case to be faster, but the log parsing takes some
time. I am still not decided if I like this change.

- new extensions:

  - preprocess_input: support for pre-processing of the input files
using Pandoc and Knitr. It can detect the file type and process it
accordingly. It supports Markdown, RMarkdown, Rtex, Rnw etc.

  - collapsetoc: useful for minitoces in multi page HTML files - it
created table of contents containing headers in the HTML file and top
level headers in the others. It is similar to TOCs used in
Readthedoces (https://papis.readthedocs.io/en/latest/configuration.html
for example)

- fixed lot of bugs in the ODT output
- fixed lot of other bugs

I would also like to apologize to everyone who sent me a mail during
summer and I haven't responded yet. I was somewhat overwhelmed by many
things and I am sometimes bad at responding when I am exhausted. I
hope to catch it all and respond in a near future.

Best regards,
Michal