capabilities docs update

Author: nevans

lib/net/imap.rb

@@ -1120,17 +1120,16 @@ def auth_capable?(mechanism)
     #      password:     proc { password  ||= ui.prompt_for_password },
     #      oauth2_token: proc { accesstok ||= kms.fresh_access_token },
     #    }
-    #    if    auth_capable? "OAUTHBEARER"
-    #      imap.authenticate "OAUTHBEARER",   **creds # authcid, oauth2_token
-    #    elsif auth_capable? "XOAUTH2"
-    #      imap.authenticate "XOAUTH2",       **creds # authcid, oauth2_token
-    #    elsif auth_capable? "SCRAM-SHA-256"
-    #      imap.authenticate "SCRAM-SHA-256", **creds # authcid, password
-    #    elsif auth_capable? "PLAIN"
-    #      imap.authenticate "PLAIN",         **creds # authcid, password
-    #    elsif auth_capable? "DIGEST-MD5"
-    #      imap.authenticate "DIGEST-MD5",    **creds # authcid, password
-    #    elsif auth_capable? "LOGINDISABLED"
+    #    mechanism = %w[
+    #      OAUTHBEARER XOAUTH2
+    #      SCRAM-SHA-256 SCRAM-SHA-1
+    #      PLAIN
+    #    ].find {|m|
+    #      imap.auth_capable?(m)
+    #    }
+    #    if mechanism
+    #      imap.authenticate mechanism, **creds
+    #    elsif capable? "LOGINDISABLED"
     #      raise "the server has disabled login"
     #    else
     #      imap.login username, password