Add clarity that the Online mode can use cached data

Author: bartonjs

xml/System.Security.Cryptography.X509Certificates/X509RevocationMode.xml

@@ -113,7 +113,7 @@
       </ReturnValue>
       <MemberValue>0</MemberValue>
       <Docs>
-        <summary>No revocation check is performed on the certificate.</summary>
+        <summary>Specifies that revocation checks should not be performed.</summary>
       </Docs>
     </Member>
     <Member MemberName="Offline">
@@ -157,7 +157,7 @@
       </ReturnValue>
       <MemberValue>2</MemberValue>
       <Docs>
-        <summary>A revocation check is made using a cached certificate revocation list (CRL).</summary>
+        <summary>Revocation checks can only be performed with cached revocation data.</summary>
       </Docs>
     </Member>
     <Member MemberName="Online">
@@ -201,7 +201,7 @@
       </ReturnValue>
       <MemberValue>1</MemberValue>
       <Docs>
-        <summary>A revocation check is made using an online certificate revocation list (CRL).</summary>
+        <summary>Revocation checks that are not possible with cached revocation data should attempt to make live requests to update the cache.</summary>
       </Docs>
     </Member>
   </Members>