Fix commenting convention. Remove unnecessary leading * in custom docstrings.

Fix commenting convention.  Remove unnecessary leading * in custom docstrings.
(flyspell-emacs): Remove unused var.
(flyspell-accept-buffer-local-defs): Use save-current-buffer.
(flyspell-debug-signal-no-check, flyspell-debug-signal-changed-checked)
(flyspell-debug-signal-pre-word-checked, flyspell-post-command-hook)
(flyspell-debug-signal-word-checked): Use with-current-buffer.
(make-flyspell-overlay): Don't locally reuse a global name.
(flyspell-highlight-incorrect-region)
(flyspell-highlight-duplicate-region): Use flyspell-unhighlight-at.
(flyspell-check-previous-highlighted-word): Use flyspell-overlay-p.
(flyspell-notify-misspell): Remove unused args `start' and `end'.
(flyspell-word): Adjust call accordingly.  Use ispell-send-string.
Wrap calls to accept-process-output inside with-local-quit since it's
often called from a post-command-hook.
(flyspell-correct-word, flyspell-auto-correct-word): Use ispell-send-string.
(flyspell-xemacs-popup): Remove unused arg `event'.  Update call.