data/xbps.d.5: correct name of conf key for staging

Author: classabbyamp

data/xbps.d.5

@@ -121,7 +121,7 @@ example:
 .El
 .It Sy rootdir=path
 Sets the default root directory.
-.It Sy staged=true|false
+.It Sy staging=true|false
 Enables or disables the use of staged packages in remote repositories.
 .It Sy syslog=true|false
 Enables or disables syslog logging. Enabled by default.