qemu-doc.texi: Rename references to 2.13 to 3.0

Update references to 2.13 to read 3.0, since that's the
number we're using for the next release.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-id: 20180522104000.9044-6-peter.maydell@linaro.org

qemu-doc.texi

@@ -2917,7 +2917,7 @@ The @code{-localtime} option has been replaced by @code{-rtc base=localtime}.
 
 The @code{-startdate} option has been replaced by @code{-rtc base=@var{date}}.
 
-@subsection -virtioconsole (since 2.13.0)
+@subsection -virtioconsole (since 3.0.0)
 
 Option @option{-virtioconsole} has been replaced by
 @option{-device virtconsole}.
@@ -2940,7 +2940,7 @@ from qcow2 images.
 
 The ``query-cpus'' command is replaced by the ``query-cpus-fast'' command.
 
-@subsection query-cpus-fast "arch" output member (since 2.13.0)
+@subsection query-cpus-fast "arch" output member (since 3.0.0)
 
 The ``arch'' output member of the ``query-cpus-fast'' command is
 replaced by the ``target'' output member.