Further tweaks to pipe trick documentation (follow-up Iaf365e31)

- call them pipe tricks (plural) as there's more than one
- mention double-width comma as well
- use one tab character for alignment due to double-width chars
- document reverse pipe trick

Change-Id: I27a1d04362eb3988fc1318fa1f73f69877019439
Merge "Further tweaks to pipe trick documentation (follow-up Iaf365e31)"