; Fix some recent fixes to doc strings

; Fix some recent fixes to doc strings

* lisp/whitespace.el (whitespace-empty-at-bob-regexp):
* lisp/vc/vc-dir.el (vc-dir-child-files-and-states):
* lisp/vc/vc-annotate.el
(vc-annotate-show-changeset-diff-revision-at-line):
* lisp/vc/ediff.el (ediff-merge-with-ancestor-command):
* lisp/gnus/nnvirtual.el (nnvirtual-update-xref-header)
(nnvirtual-map-article):
* lisp/emulation/viper-init.el (viper-ESC-keyseq-timeout):
* lisp/emulation/viper-cmd.el
(viper-set-parsing-style-toggling-macro):
* lisp/cedet/data-debug.el (data-debug-insert-hash-table-button):
"The first line of a doc string must be a complete sentence."
Also, fix some awkward wording in doc strings while at that.