[Inflector] Fixed pluralize "coupon"

src/Symfony/Component/Inflector/Inflector.php

@@ -231,6 +231,9 @@ final class Inflector
         // bacteria (bacterium), criteria (criterion), phenomena (phenomenon)
         ['noi', 3, true, true, 'ions'],
 
+        // coupon (coupons)
+        ['nop', 3, true, true, 'pons'],
+
         // seasons (season), treasons (treason), poisons (poison), lessons (lesson)
         ['nos', 3, true, true, 'sons'],
 

src/Symfony/Component/Inflector/Tests/InflectorTest.php

@@ -201,6 +201,7 @@ class InflectorTest extends TestCase
             ['crisis', 'crises'],
             ['criteria', 'criterion'],
             ['cup', 'cups'],
+            ['coupon', 'coupons'],
             ['data', 'data'],
             ['day', 'days'],
             ['disco', 'discos'],