Fix spelling error in rotctl.c help and add offset settings to rotctl.1

doc/man1/rotctl.1

@@ -23,6 +23,8 @@ rotctl \- control antenna rotators
 .OP \-s baud
 .OP \-t char
 .OP \-C parm=val
+.OP \-o azoffset
+.OP \-O eloffset
 .RB [ \-v [ \-Z ]]
 .RB [ command | \- ]
 .YS
@@ -131,6 +133,15 @@ The semicolon (\(oq;\(cq) is a common terminator for rotators that accept
 ASCII character strings.
 .
 .TP
+.BR \-o ", " \-\-set\-azoffset
+Azimuth correction floating point -- during set value is added, during get value is subtracted.
+.
+.TP
+.BR \-O ", " \-\-set\-eloffset
+Elevation correction floating point -- during set value is added, during get value is subtracted.
+.
+.
+.TP
 .BR \-L ", " \-\-show\-conf
 List all configuration parameters for the rotator defined with
 .B \-m

tests/rotctl.c

@@ -509,8 +509,8 @@ void usage()
         "  -s, --serial-speed=BAUD       set serial speed of the serial port\n"
         "  -t, --send-cmd-term=CHAR      set send_cmd command termination char\n"
         "  -C, --set-conf=PARM=VAL       set config parameters\n"
-        "  -o, --set-azoffset==VAL       set offset for azimuth\n"
-        "  -O, --set-eloffset==VAL       set offset for elevation\n"
+        "  -o, --set-azoffset=VAL        set offset for azimuth\n"
+        "  -O, --set-eloffset=VAL        set offset for elevation\n"
         "  -L, --show-conf               list all config parameters\n"
         "  -l, --list                    list all model numbers and exit\n"
         "  -u, --dump-caps               dump capabilities and exit\n"