bug#15810: 24.3.50; inappropriate text in (emacs) `Echo Area'

[Drew Adams]

This text has no business being there:

(We have not explained buffers yet; see *note Buffers::,
for more information about them.)

(We have not
explained variables either; see *note Variables::, for more information
about them.)

Include the cross references, but drop the unhelpful commentary.

This text seems based on an assumption that reading is linear, from page
1 to the current page.  This was not true back in the 1980s, when Info
was created, and it certainly is not true today.  Reserve such text (if
at all) for the printed manual.

In GNU Emacs 24.3.50.1 (i686-pc-mingw32)
 of 2013-10-19 on LEG570
Bzr revision: 114715 rgm@gnu.org-20131019023520-s8mwtib7xcx9e05w
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --enable-checking 'CFLAGS=-O0 -g3' CPPFLAGS=-DGLYPH_DEBUG=1'