* add block and extend feature
* constify, code cleaning
* update single include
* add html language to readme
* clean tests
* constantify, update year
* add function to get position of current token
* new exception parser_error with error location
* parser throws parser_error with error location
* update single include
* get error position in text
* bump to 2.3
* subclass exceptions
* update single include from every directory
* center badges in readme
* github ci windows, mac
* use default compiler
* check ci
* fix ci
* test ci
* fix ci
* fix ci
* test ci
* badges to github action
* add check for single include
* fix check
* check (should fail)
* fix all ci
* add artifact in single include ci
* update to newest nlohmann/json
* move unit tests to doctest
* move to json v3.6.1
* add function to get position of current token
* new exception parser_error with error location
* parser throws parser_error with error location
* update single include
* get error position in text
* bump to 2.3
* subclass exceptions
Co-authored-by: pantor <lars.berscheid@online.de>