Remove wiki from user algorithms. Refs #9592.
Remove wiki from remaining algorithms. Refs #9592.

- Interestingly, CentroidPeaks has an .rst file, which also has the wiki!
- SliceMDHisto on the other hand, did not have an .rst file.
Remove incorrectly named algorithm rst

It has actually been dealt with elsewhere anyway.
Refs #9592
re #9592 remaining wiki usages from algorithms that came in late
Merge remote-tracking branch 'origin/feature/9592_remove_final_wiki'