server: Fix formatting of credential provider note (#1023)

* server: Fix formatting of credential provider note

* Update server/credential_provider.go

Co-authored-by: ccoVeille <[email protected]>

---------

Co-authored-by: ccoVeille <[email protected]>

Author: dveeden

server/credential_provider.go

@@ -4,7 +4,9 @@ import "sync"
 
 // interface for user credential provider
 // hint: can be extended for more functionality
-// =================================IMPORTANT NOTE===============================
+//
+// # Important Note
+//
 // if the password in a third-party credential provider could be updated at runtime, we have to invalidate the caching
 // for 'caching_sha2_password' by calling 'func (s *Server)InvalidateCache(string, string)'.
 type CredentialProvider interface {