ASTERISK-24419, fix incorrect syntax for setting language in extensions.conf.sample

git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/1.8@426295 f38db490-d61c-443f-a65b-d21fe96a405b
ASTERISK-24323, fix bug in documentation of AGI STREAM FILE CONTROL

git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/1.8@426363 f38db490-d61c-443f-a65b-d21fe96a405b
ASTERISK-23512, correct inaccurate comment in manager.conf.sample

git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/1.8@426460 f38db490-d61c-443f-a65b-d21fe96a405b