fix xref letter case in threats

Author: s-choudhury

input/authserver.xml

@@ -386,11 +386,11 @@
           <rationale>Mitigates the threat by utilizing RadSec to establish a trusted channel with the relying party.</rationale>
           <addressed-by>FIA_PSK_EXT.1/AuthSvr (selection-based)</addressed-by>
           <rationale>Mitigates the threat by using a pre-shared key as the mechanism by which it authenticates itself to the relying party.</rationale>
-          <addressed-by>FIA_X509_EXT.1 (from <xref to="x509"/>)</addressed-by>
+          <addressed-by>FIA_X509_EXT.1 (from <xref to="X509"/>)</addressed-by>
           <rationale>Mitigates the threat by authenticating relying parties via X.509 certificates.</rationale>
-          <addressed-by>FIA_X509_EXT.2 (from <xref to="x509"/>)</addressed-by>
+          <addressed-by>FIA_X509_EXT.2 (from <xref to="X509"/>)</addressed-by>
           <rationale>Mitigates the threat by authenticating relying parties via X.509 certificates.</rationale>
-          <addressed-by>FIA_X509_EXT.3 (from <xref to="x509"/>)</addressed-by>
+          <addressed-by>FIA_X509_EXT.3 (from <xref to="X509"/>)</addressed-by>
           <rationale>Mitigates the threat by implementing a method for the TOE to obtain its own certificate for mutually-authenticated TLS or DTLS.</rationale>
           <addressed-by>FTP_ITC.1/NAS</addressed-by>
           <rationale>Mitigates the threat by utilizing a cryptographically secure trusted channel with a relying party that allows mutual authentication with the relying party.</rationale>