defTable to conceptChunkTable renaming missing in the wiki

[sarrasoussia]

After finishing this #4047 , the wiki still needs to be updated:

[balacij]

The conceptChunkTable was also removed in #4320. I think it's fine to leave that page as-is. The goal of the page is to show a few tricks on how to use grep/rg, not really specifically to show what the ChunkDB used to be.