docs/zh_CN: add Alex Shi as Chinese documentation maintainer

It's kind of fun to learn and tranlate kernel docs into Chinese. I'd
like to help people on this work. And willing to be the 'blamed' people
if sth wrong in this area. :)

Signed-off-by: Alex Shi <[email protected]>
Cc: Harry Wei <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Jonathan Corbet <[email protected]>

MAINTAINERS

@@ -3728,6 +3728,7 @@ F:	scripts/checkpatch.pl
 
 CHINESE DOCUMENTATION
 M:	Harry Wei <[email protected]>
+M:	Alex Shi <[email protected]>
 L:	[email protected] (subscribers-only)
 S:	Maintained
 F:	Documentation/translations/zh_CN/