The -oque ending is used in “Argot”, an informal form of French - it’s not a separate language, rather just the “popular register”.
What’s going on with Canuck ( also written Canoque, Canaque) is called “resuffixation” - - the word first gets shortened and then a suffix gets stuck on. In informal English, Australian and Oklahoman get shortened to Aus- and Ok- and then -ie gets tacked on to form “Aussie” and “Okie”.
There are quite a few “suffixes argotiques” besides -oque, like -uche, or -ard - for a fuller discussion see “Dictionnaire de l’argot francais et de ses origines” by Jean-Paul Colin.
-oque is still used in popular French today, but it goes back hundreds of years . “The system of
of the deformation of endings…appeared at the start of the 17th Century and developed little by little under the influence of several Southern European suffixes, particularly Italian”, Albert Dauzat, “Les Argots”, (Paris, 1929). I understand there is also a well-developed system of suffixes in Spanish.
Argot is not written down that much in French, since it is a spoken form of the language, but some writers, like Francois Villon, Vidocq and Celine have written in it.
I notice that many sources give ridiculous etymologies for ‘Canuck’ - one even suggested it came from Hawaiian, and another thought it was from the Irish family name ‘Connaught’, and most French-Canadian dictionaries think it is a perjorative word from English. I would think that most people in Canada would not be that familiar with argot, even if they were French-Canadian, as they do not use this form in popular speech, perhaps because their ancestors came from Normandy and other parts of North-west France.
Some French-Canadians do take offense at the informality of the word ‘Canuck’, but others are proud to use it - There is a major camping and outdoor gear manufacturer in Quebec called “Kanuk”.