Feature summary (what you would like to be able to do and where):
The language field accepts a series of values, some of which are equivalent. For example es and spanish.

Consider adding a compare function that takes these equivalencies into account, such that es and spanish return a 100% score.

Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):
Citoid may be returning spanish (because that's what the Zotero translator may return). The user may be unaware of this when defining a translation rule, and enter es instead (see T308328). The same or another user may legitimately use the Citoid selection step in the corresponding template field. This would render a misleading mismatch between the translation output and the expected output.

Benefits (why should this be implemented?):
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