I did a quick review of this.
The patch is just a doc typo fix and it applies cleanly to master (as of this email). I was able to build the docs,
andthey look ok.
Fixing the abs/hash bracketing seems clear. The wasn't sure about rewriting "mod(i, bj)" as "mod(i, j)", because there
couldbe some convention about parameter names, but I can't think of anything the "b" could be in the case of mod.
Edmund