bug#50792: 26.3; Key notation typos

[Drew Adams <drew.adams@oracle.com>]

1. In (emacs) Spelling:

'<ESC>-<TAB>' should instead be '<ESC> <TAB>' (as it is elsewhere in the
manual).  No modifier syntax.

2. In (emacs) Editing Binary Files:

'C-h a hexl-<RET>' should be something else.  The space after C-h and
after a doesn't mean type a SPC char, but you expect readers to see
hexl- as meaning type those 5 chars.  At least add a space before <RET>,
but even that isn't a real fix.  The notation -<...> should be used only
following a modifier, as in M-<right>.

3. Same problem as #2, in (emacs) Mac/GNUstep Events.

'M-x ns-service-<TAB>' 

4. (emacs) Windows Keyboard.

Is `W' introduced anywhere as a modifier key?  What is 'W-<SPC>'?

5. Throuhout the Emacs manual, sometimes it's C-<BREAK>, sometimes it's
C-<Break>.  (And I don't mean in code, e.g., as an arg to `kbd'.)  Is
this correct?  The contexts seem to be the same/similar: "pressing" or
"using" such a key sequence.  There are other, similar such seeming
inconsistencies / problems with other modified function keys.

In GNU Emacs 26.3 (build 1, x86_64-w64-mingw32)
 of 2019-08-29
Repository revision: 96dd0196c28bc36779584e47fffcca433c9309cd
Windowing system distributor `Microsoft Corp.', version 10.0.19042
Configured using:
 `configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static -g3''