Add precision on playlist_year +/- properties (generaldata.ini) (#2156

)

docs/user-guide/solver/04-parameters.md

@@ -792,13 +792,15 @@ They are **required** if [user-playlist](#user-playlist) is set to `true`.
 ---
 #### playlist_year
 - **Expected value:** `+ =` or `- =`, followed by a positive integer (example: `playlist_year + = 5`)
-- **Required:** **yes**, if [user-playlist](#user-playlist) is set to `true`.
+- **Required:** **yes**, if [user-playlist](#user-playlist) is set to `true`, ignored otherwise.
 - **Usage:**
     - for every Monte-Carlo year that you want the Antares Simulator to **study**, add the parameter entry
       `playlist_year + = i`, where `i` is the index of the year.
     - for every Monte-Carlo year that you want the Antares Simulator to **skip**, add the parameter entry
       `playlist_year - = i`, where `i` is the index of the year.
 
+_Please note that by convention, the first year has index 0._
+
 ---
 #### playlist_year_weight
 [//]: # (TODO: document this parameter)