Documentation: X509_V_ERR_CERT_CHAIN_TOO_LONG is not unused

The Error `X509_V_ERR_CERT_CHAIN_TOO_LONG` is not unused. See e.g. here:

https://github.com/openssl/openssl/blob/598bd7741568a1aae678e5472f18aae1ab991e8d/crypto/x509/x509_vfy.c#L3318-L3319

CLA: trivial

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18330)
diff --git a/doc/man3/X509_STORE_CTX_get_error.pod b/doc/man3/X509_STORE_CTX_get_error.pod
index 901113c..90ebcac 100644
--- a/doc/man3/X509_STORE_CTX_get_error.pod
+++ b/doc/man3/X509_STORE_CTX_get_error.pod
@@ -212,7 +212,7 @@
 
 =item B<X509_V_ERR_CERT_CHAIN_TOO_LONG: certificate chain too long>
 
-The certificate chain length is greater than the supplied maximum depth. Unused.
+The certificate chain length is greater than the supplied maximum depth.
 
 =item B<X509_V_ERR_CERT_REVOKED: certificate revoked>