* lisp/emacs-lisp/lisp-mnt.el (lm-section-end): Always end before the

* lisp/emacs-lisp/lisp-mnt.el (lm-section-end): Always end before the
following non-comment text.
(lm-header-multiline): Continuation lines need to be indented more than
the first line.
(lm-homepage): New function.
(lm-with-file): Don't be confused if narrowing is in effect.
* doc/lispref/tips.texi (Library Headers): New header keyword `Homepage'.
Make continuation lines syntax more precise.

Fixes: debbugs:13207