docs/devel/writing-monitor-commands: Minor improvements

Avoid "JSON" when talking about the QAPI schema syntax.  Capitalize
QEMU.  Don't claim all HMP commands live in monitor/hmp-cmds.c (this
was never true).  Fix punctuation and drop inappropriate "the" here
and there.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240227115617.237875-3-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
1 file changed