Value of contributions to Wikipedia when applying for academic jobs
I have never heard of any weight given to contributing to Wikipedia for any aspects of academic evaluation. I personally wouldn't attach any weight to it either, especially given that many articles have a long history of edits and figuring out exactly who contributed what can be difficult.

If you want to include this on your CV or similar, I would mention it under "Misc." or "Other" or something like that. If you have made significant contributions to other similar sites (e.g. stackoverflow) I would put that into the same paragraph. I would definitely avoid trying to make it appear as one of the major things you have done. Wikipedia is regarded rather suspiciously in general because it can be an unreliable source. While contributing to it could be a bonus, it won't be a significant one.