update comment

src/Entity/ExternalDataTheoreticalCotisationRule.php

@@ -9,8 +9,9 @@ use Doctrine\ORM\Mapping as ORM;
  * @ORM\Entity(repositoryClass=ExternalDataTheoreticalCotisationRuleRepository::class)
  * 
  * This class stores data used to calculate the theoritical cotisation amount of a Adherent.
- * For each allocation bracket (allocationAmount), and for each income bracket (incomeMin < x <= incomeMax),
- *  cotisation is calculated as such : f(x) = coef * x + intercept ;
+ * For each allocation bracket (allocationAmount), and for each income bracket (incomeMin < x <= incomeMax):
+ *  if fixedValue is set: f(x) = fixedValue
+ *  else cotisation is calculated as such : f(x) = coef * x + intercept ;
  *      with x as the Adherent's monthly income.
  * 
  * This data is used for visualisation purposes in an external Metabase instance.