docs: Fixed angle bracket typo for task locking command line instructions.

$ rm /tmp/device_owner.xml

$ echo "<?xml version='1.0' encoding='utf-8' standalone='yes' ?>"

>> /tmp/device_owner.xml

$ echo "&device-owner package=\"<your_device_owner_package>\"

$ echo "<device-owner package=\"<your_device_owner_package>\"

name=\"*<your_organization_name>\" />" >> /tmp/device_owner.xml

$ adb push /tmp/device_owner.xml /data/system/device_owner.xml

$ adb reboot