minor #15617 [Mailer] Fixing "envelope recipient" (ThomasLandauer)

This PR was merged into the 5.3 branch.

Discussion
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[Mailer] Fixing "envelope recipient"

Second part of #15240

The link `SMTP session` depends on #15616

Commits
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18fb7c3 Fixing "envelope recipient"

Author: javiereguiluz

reference/configuration/framework.rst

@@ -3381,8 +3381,8 @@ recipients
 
 **type**: ``array``
 
-Recipients used by the ``Mailer``. Keep in mind that this setting override
-recipients set in the code.
+The "envelope recipient" which is used as the value of ``RCPT TO``  during the
+the `SMTP session`_. This value overrides any other sender set in the code.
 
 .. configuration-block::