Minor: Plugin: Justification: Improve documentation

plugin/justification/lang/english.php

@@ -1,7 +1,7 @@
 <?php
 
 $strings['plugin_title'] = "Justification Plugin";
-$strings['plugin_comment'] = "";
+$strings['plugin_comment'] = "Requires documents from students as administrative justification.";
 
 $strings['tool_enable'] = "Enable";
 

plugin/justification/lang/french.php

@@ -1,7 +1,7 @@
 <?php
 
 $strings['plugin_title'] = "Justification Plugin";
-$strings['plugin_comment'] = "";
+$strings['plugin_comment'] = "Demande des documents à valeur de justification administrative.";
 $strings['tool_enable'] = "Activer le plugin";
 
 $strings['ValidityDuration'] = "Durée de validité en jour";

plugin/justification/lang/spanish.php

@@ -1,7 +1,7 @@
 <?php
 
 $strings['plugin_title'] = "Justification Plugin";
-$strings['plugin_comment'] = "";
+$strings['plugin_comment'] = "Exige la subida de documentos de parte de los alumnos para validación de temas administrativos.";
 $strings['tool_enable'] = "Activar el plugin";
 
 $strings['ValidityDuration'] = "Periodo de validez en días";