qemu-options.hx: Fix minor issues in icount documentation

qemu-options.hx: Fix minor issues in icount documentation

The documentation for the icount documentation has some minor issues:
 * in a couple of places it says "sleep=on|off" when in the context of the
   sentence it means specifically "sleep=on"
 * the synopsis line for the documentation has drifted out of sync
   with the synopsis line in the DEF() macro (used for "-help" output)
 * the synopsis line in the DEF() macro is missing a "][" between
   the sleep= part and the rr= part
 * the synopsis line doesn't indicate that rrsnapshot is an optional
   part of the rr=mode,rrfile=filename subgrouping
 * we don't document that sleep=on can't be used with shift=auto
   or align=on
 * the rr option description had some minor grammar and formatting
   errors and was a bit terse
 * in commit f1f4b57e88ff in 2015 the documentation of the sleep=
   suboption got added between the two paragraphs defining general
   behaviour of the icount option. This meant that the second
   paragraph talking about the behaviour of "this option" reads as
   if it's talking about sleep=on, when it's really describing -icount
   as a whole. The paragraph is better moved back up to above the
   sleep= section.
 * the summary text displayed in "-help" output didn't mention
   the record-and-replay part

Fix these errors.

Fixes: https://bugs.launchpad.net/qemu/+bug/1774412
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201121213506.15599-1-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>