docs: remove a bunch of stray CRs

A pair of documentation patches introduced a bunch of unwanted
carriage-return characters into the docs.  Remove them, and chase away the
ghost of DOS for another day.

Fixes: a016e092 ("docs: admin-guide: dell_rbu: Improve formatting and spelling")
Fixes: bdd68860 ("Documentation: networking: device drivers: Remove stray asterisks")
Signed-off-by: Jonathan Corbet <corbet@lwn.net>