[WIP] Add an XML schema for documentation
Created by: Calinou
Don't merge yet, --doctool
needs to be modified to not discard the schema declarations in each XML file.
This makes it easier to spot syntax errors when editing the class reference. The schema is referenced locally so validation can still work offline.
Tested with the vscode-xml Visual Studio Code add-on.
PS: Is there a way to forbid an element from containing anything (even text)? This would be very nice to have for <argument>
elements, as they can't have a description.