Simply import pseudocodigo.xml and pseudocodigo_darkmode.xml to Notepad++ by going to Menu -> Language -> Define your language -> Import option.
Important: After that, close Notepad++ and go to Language -> pseudocodigo.
The pseudocodigo extension is
<my_algorithm_name>.pseudo
https://notepad-plus-plus.org/community/topic/12833/custom-autocomplete-file-for-xml-language/11