Disallow ? in names.
 [rsc] --rw-rw-r-- M 195156 glenda sys 11573 Dec 13 13:35 sys/src/cmd/wikifs/io.c
	/n/sourcesdump/2005/1213/plan9/sys/src/cmd/wikifs/io.c:445,451 - 
	/n/sourcesdump/2005/1214/plan9/sys/src/cmd/wikifs/io.c:445,451
	  		return -1;
	  	}
	  
	- 	if(title[0]=='\0' || strpbrk(title, "/<>:")){
	+ 	if(title[0]=='\0' || strpbrk(title, "/<>:?")){
	  		werrstr("invalid character in name");
	  		return -1;
	  	}