Mediawiki uses a special markup they call wikicode. You should definitely just check the Help section, it has a list of all the basic wikicode examples.
It is coding just like HTML is coding in the technical sense. (Encoding data into a certain format)
You probably meant programming which it isn't, just like HTML isn't. Although Wikicode is more programming than HTML as it includes basic parser function hooks. However those are technically all written in php. It still gives you the possibility to do basic processing though. Without data storage it'll never really be turing complete though, since you can't modify articles as runtime, even though you could technically use them to store data.
But for all intents and purposes, wikicode is coding.