Fix options in hbal manpage

hbal doesn't have any "-o" option, but on the other hand supports -S
(described below, but not present in the short summary)

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

man/hbal.rst

@@ -39,7 +39,7 @@ Reporting options:
 **[ -C[ *file* ] ]**
 **[ -p[ *fields* ] ]**
 **[ \--print-instances ]**
-**[ -o ]**
+**[ -S *file* ]**
 **[ -v... | -q ]**