(spam-find-spam, spam-enter-list): Doc fixes.

(spam-find-spam, spam-enter-list): Doc fixes.
(spam-split-symbolic-return-positive): Reflow docstring.
(spam-backends, spam-summary-exit-behavior,
spam-mark-ham-unread-before-move-from-spam-group,
spam-summary-score-preferred-header, spam-sa-learn-spam-switch,
spam-sa-learn-ham-switch, spam-sa-learn-unregister-switch, spam-clear-cache,
spam-backend-check, spam-install-backend, spam-install-statistical-backend,
spam-list-of-processors, spam-group-processor-p, spam-split,
spam-bogofilter-score, spam-bsfilter-score, spam-check-bsfilter,
spam-crm114-score, spam-check-crm114, spam-initialize, spam-unload-hook):
Fix typos in docstrings.