Add missing comments

Author: bingyanglin

crates/iota-core/src/authority.rs

@@ -4333,6 +4333,9 @@ impl AuthorityState {
         Some(res)
     }
 
+    /// Returns the new protocol version and system packages that the network
+    /// has voted to upgrade to. If the proposed protocol version is not
+    /// supported, None is returned.
     fn is_protocol_version_supported_v1(
         current_protocol_version: ProtocolVersion,
         proposed_protocol_version: ProtocolVersion,
@@ -4422,6 +4425,9 @@ impl AuthorityState {
             })
     }
 
+    /// Selects the highest supported protocol version and system packages that
+    /// the network has voted to upgrade to. If no upgrade is supported,
+    /// returns the current protocol version and system packages.
     fn choose_protocol_version_and_system_packages_v1(
         current_protocol_version: ProtocolVersion,
         protocol_config: &ProtocolConfig,