bug#20371: 25.0.50; Tutorial first page: tell users how to quit the tutorial

[Drew Adams]

The top of the tutorial tells you how to quit Emacs.  That's good.
Perhaps it should also tell you how to quit the tutorial and return to
your previous buffer.

See this SO question, for an expression of one confused user's
frustration.  S?he "accidentally" fell into the tutorial and was worried
about how to get back to the original buffer.
http://stackoverflow.com/q/29727620/729907



In GNU Emacs 25.0.50.1 (i686-pc-mingw32)
 of 2014-10-20 on LEG570
Bzr revision: 118168 rgm@gnu.org-20141020195941-icp42t8ttcnud09g
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --enable-checking=yes,glyphs CPPFLAGS=-DGLYPH_DEBUG=1'