bug#15547: 24.3.50; doc string of `isearch-cmds'

[Drew Adams]

1. The first element of the vector is missing from the description.  It
is the symbol `cl-struct-isearch--state'.  The vector has 13 elements,
not 12.

2. It would be a little clearer to say that the value is a *list* that
is *used* as a stack.

3. Better to just say "vectors", not "sets", since the order is
important (and the reader is right-away presented with the vector
description).



In GNU Emacs 24.3.50.1 (i686-pc-mingw32)
 of 2013-09-30 on LEG570
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --enable-checking 'CFLAGS=-O0 -g3' CPPFLAGS=-DGLYPH_DEBUG=1'