Documentation doesn’t solve the problem of Q/A situations.

Internal Stack Exchanfes are (were? I’m not sure whether they discontinued it…my old company had one but new one doesn’t) is really good at converting chat style communication into a permanent easily searchable record that can also be easily updated.

You can also avoid many of the pitfalls with stack overflow around over aggressive moderation (not really needed since the volume of questions won’t be as high), or inappropriate commenting of any sort (reach out to the individual directly or even to their manager), etc.