Fix typo in libreoffice man page.

Change-Id: Ieb3e74630e48feaf69f5d58e9b7eb57779033356
Reviewed-on: https://gerrit.libreoffice.org/2610Reviewed-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>
Tested-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>

sysui/desktop/man/libreoffice.1

@@ -122,7 +122,7 @@ or the kill command (UNIX based systems).
 .TP
 \fB\-\-infilter="<filter>"\fR
 Force an input filter type if possible.
-For example -infilter="Calc Office Open XML" only
+For example \-\-infilter="Calc Office Open XML" only
 
 .TP
 \fB\-\-math\fR