doc: update notes about GCM decryption

Given that #17825 and
#20039 have landed on master, this
statement is no longer true.

PR-URL: #21445
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

doc/api/crypto.md

@@ -441,16 +441,8 @@ supported), the `decipher.setAuthTag()` method is used to pass in the
 received _authentication tag_. If no tag is provided, or if the cipher text
 has been tampered with, [`decipher.final()`][] will throw, indicating that the
 cipher text should be discarded due to failed authentication. If the tag length
-is invalid according to [NIST SP 800-38D][], `decipher.setAuthTag()` will throw
-an error.
-
-Note that this Node.js version does not verify the length of GCM authentication
-tags. Such a check *must* be implemented by applications and is crucial to the
-authenticity of the encrypted data, otherwise, an attacker can use an
-arbitrarily short authentication tag to increase the chances of successfully
-passing authentication (up to 0.39%). It is highly recommended to associate one
-of the values 16, 15, 14, 13, 12, 8 or 4 bytes with each key, and to only permit
-authentication tags of that length, see [NIST SP 800-38D][].
+is invalid according to [NIST SP 800-38D][] or does not match the value of the
+`authTagLength` option, `decipher.setAuthTag()` will throw an error.
 
 The `decipher.setAuthTag()` method must be called before
 [`decipher.final()`][].