[Uid] Clarify the format returned by getTime()

src/Symfony/Component/Uid/Ulid.php

@@ -104,6 +104,9 @@ class Ulid extends AbstractUid
         return $this->uid;
     }
 
+    /**
+     * @return float Seconds since the Unix epoch 1970-01-01 00:00:00
+     */
     public function getTime(): float
     {
         $time = strtr(substr($this->uid, 0, 10), 'ABCDEFGHJKMNPQRSTVWXYZ', 'abcdefghijklmnopqrstuv');

src/Symfony/Component/Uid/UuidV1.php

@@ -31,6 +31,9 @@ class UuidV1 extends Uuid
         }
     }
 
+    /**
+     * @return float Seconds since the Unix epoch 1970-01-01 00:00:00
+     */
     public function getTime(): float
     {
         $time = '0'.substr($this->uid, 15, 3).substr($this->uid, 9, 4).substr($this->uid, 0, 8);

src/Symfony/Component/Uid/UuidV6.php

@@ -32,6 +32,9 @@ class UuidV6 extends Uuid
         }
     }
 
+    /**
+     * @return float Seconds since the Unix epoch 1970-01-01 00:00:00
+     */
     public function getTime(): float
     {
         $time = '0'.substr($this->uid, 0, 8).substr($this->uid, 9, 4).substr($this->uid, 15, 3);