README: fixed an invalid URL address of UniRec statup configuration

Author: Lukas955

doc/sphinx/configuration.rst

@@ -180,7 +180,7 @@ of IPFIXcol. Always keep in mind that you should modify a configuration to fit y
 :`multiOutput <../data/configs/multiOutput.xml>`_:
     Receive flow data over TCP and store them in a nfdump compatible format on a local drive
     and simultaneously send to a remote host as JSON.
-:`tcp2unirec <../data/configs/tcp2unirec.xml>_`:
+:`tcp2unirec <../data/configs/tcp2unirec.xml>`_:
     Receive flow data over TCP, convert them into UniRec format and send via TCP TRAP
     communication interface (port 8000).