wiki: correct four stale parity rows !281

Four rows claimed the web lacks something it has, and one capability had no row. Each checked against the code:

• build cancel — build.html:8 posts to /{owner}/{repo}/builds/{n}/cancel.
• profile set — account.html:10, field=profile, dispatched at account.go:168.
• choose body markup, issues and MRs — issuenew.html:9 and mrnew.html:19 both render the formatpicker partial.
• request a review — shipped in a2d1580 with no row; mr.html:134 posts to /review-request.

The paragraphs that explained the old no are rewritten with them, including the one still stating that nothing asks a particular person for a review.

The iOS column is left as no on the new row and unchanged elsewhere — this repository cannot verify the client, so nothing here was raised on that column.

command reference stays no: there is no /help route.