docs: explain what the roll_off parameter means
@@ -275,7 +275,9 @@ The modes are defined as follows:
+----------------------+-----------+-----------------------------------------+
| ``bit_rate`` | (number) | in bit/s |
+----------------------+-----------+-----------------------------------------+
-| ``roll_off`` | (number) | Not used. |
+| ``roll_off`` | (number) | Pure number between 0 and 1. TX signal |
+| | | roll-off shape. Used by Raman-aware |
+| | | simulation code. |
+----------------------+-----------+-----------------------------------------+
| ``tx_osnr`` | (number) | In dB. OSNR out from transponder. |
+----------------------+-----------+-----------------------------------------+
@@ -469,7 +471,9 @@ one power/channel definition.
+----------------------+-----------+-------------------------------------------+
| ``spacing`` | (number) | In Hz. Carrier spacing. |
+----------------------+-----------+-------------------------------------------+
-| ``roll_off`` | (number) | Not used. |
+| ``roll_off`` | (number) | Pure number between 0 and 1. TX signal |
+| | | roll-off shape. Used by Raman-aware |
+| | | simulation code. |
+----------------------+-----------+-------------------------------------------+
| ``tx_osnr`` | (number) | In dB. OSNR out from transponder. |
+----------------------+-----------+-------------------------------------------+
