Small docstring fixes.

* nrepl.el (nrepl-connection-buffer-name, nrepl-buffer-ns)
(nrepl-tab-command, nrepl-macroexpand-expr-inplace)
(nrepl-wrap-history, nrepl-history-read-filename)
(nrepl-history-load, nrepl-history-save, nrepl-log-events)
(nrepl-send-string-sync, nrepl-send-input, nrepl-return)
(nrepl-recenter-if-needed, nrepl-find-and-clear-repl-buffer)
(nrepl-find-or-create-repl-buffer, nrepl-ido-form)
(nrepl-load-file-core, nrepl-load-file)
(nrepl-possibly-disable-on-existing-clojure-buffers)
(nrepl-close-ancilliary-buffers, nrepl-default-port): Small
docstring fixes.