Other than that it doesn't matter to me what anyone calls it.
You are 100% to call it whatever you want. But a key/value pair is commonly referred to as a dictionary... or a hash table which is a dictionary data type. This isn't exclusive to Python in the least.
"Commonly referred" depends on the programming language in question. For example in many other languages it's commonly called an array or collection and never a dictionary.
If you look at the part you quoted, YAML calls it mappings.
The proper computer science terminology would be associative array.
The best thing to do is to call it exactly what the language or software you are referring to calls it. If Ansible wants you to create what it has named in their documentation as a dictionary in YAML, that's what you refer to it as. Otherwise, someone who is familiar with Ansible and it's documentation won't know what the hell you are talking about if you call it your own thing.
I can agree with that point of view - YAML in the context of Ansible.
So you'd call it dictionaries then. And lists.