docs: support \C-c\C-n for in editor NEWS browsing.

* lib/zmacs/commands/help.zl (view-emacs-news): Display NEWS in a
read-only buffer.
* lib/zmacs/default-bindings-el.lua: Bind \C-c\C-n and variants
to view-emacs-news.
* NEWS: Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
maint: mention configure free installs in NEWS.

* NEWS (Build-related): Note configure-free installation support.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
maint: note Zile direction changes in NEWS.

* NEWS (Miscellaneous): Note changes to Zile.
(Zmacs): Note zmacs provides functionality formerly known as zile.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
zmacs: set help resource buffers to unmodified.

* lib/zmacs/commands/help.zl (find_or_create_buffer_from_module):
Set current buffer modified flag to false after inserting module
text content.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>