handbook/wayland: improve synopsis readability

[OwOday]

Fix small typos and improve readability in first paragraph

[lwhsu]

Thanks, please set your preferred Author line in the commit. It's discouraged to use @users.noreply.github.com. You can check it at https://patch-diff.githubusercontent.com/raw/freebsd/freebsd-doc/pull/287.patch

[OwOday]

Think I got it!

[concussious]

If doc team accepts this contribution, it will go into the tree forever, so the log and message must be helpful to the people who will be sifting and searching through it.

Please squash everything into one commit with a specific title like: handbook/wayland: improve synopsis readability and edit this pr title the same way.