It doesn't matter that much, but you could use the "in" term here instead, like:

`<text term="in" suffix="&#160;: " text-case="capitalize-first"/>`

This term is already set to "dans" by default for Canadian French (fr-CA), see https://github.com/citation-style-language/locales/blob/master/locales-fr-CA.xml#L42 . The benefit would be that if anybody wants to use this style as a template for a France French (fr-FR) style and changes the value of "default-locale", that the "dans" would automatically change to "in" (as is customary in fr-FR).