Events: updates and corrections

[grahamperrin]

Summary

Three related commits:

• https://github.com/grahamperrin/freebsd-doc/commit/3cd74efbf26667a7ff7b5198f497ff720b5c34dd
• https://github.com/grahamperrin/freebsd-doc/commit/0000f92b4bb4706c441556320c64ab99e72fdd59
• https://github.com/grahamperrin/freebsd-doc/commit/8b662704fd33df20f002cb5f1af574bc93e52ff9.

Affects:

• https://www.freebsd.org/events/ and the home page.

Origin of this diff:

• https://github.com/freebsd/freebsd-doc/compare/main...grahamperrin:freebsd-doc:events.diff.

Test Plan

Build, I guess …

[grahamperrin]

Overlap with more recent fcdac9c249 by @carlavilla.

A manual edit by me might fix things here, however I'll use this opportunity to try learning about Git at the command line for conflicts.

If I have any questions, I'll aim for chat (but probably not the #git channel).