fix a bunch of small errors in the man pages

[Humm42]

They are mostly formatting errors, such as unescaped punctuation that isn't meant to be interpreted as punctuation.

There is more that could be improved, but these changes should be the least opinion-based ones.

On many systems, some of these changes don’t usually result in different output. You can use groff -Tpdf -mdoc sam.1 to get a PDF; some things might be more easily visible there.