Function declaration updates prompted by 'make check-declare'

Function declaration updates prompted by 'make check-declare'

* lisp/emacs-lisp/package.el (lm-homepage):
* lisp/gnus/gnus-util.el (iswitchb-read-buffer):
* lisp/gnus/mm-decode.el (libxml-parse-html-region):
* lisp/gnus/mml.el (libxml-parse-html-region):
* lisp/gnus/nnrss.el (libxml-parse-html-region):
* lisp/net/eww.el (libxml-parse-html-region):
* lisp/net/shr.el (libxml-parse-html-region):
* lisp/vc/vc-bzr.el (vc-annotate-convert-time):
* lisp/vc/vc-cvs.el (vc-annotate-convert-time):
* lisp/vc/vc-git.el (vc-annotate-convert-time):
* lisp/vc/vc-hg.el (vc-annotate-convert-time):
* lisp/vc/vc-mtn.el (vc-annotate-convert-time):
* lisp/vc/vc-rcs.el (vc-annotate-convert-time):
Update declaration.