Ruby: update alert message test output

Author: alexrford

ruby/ql/test/query-tests/experimental/cwe-347/EmptyJWTSecret.expected

@@ -1,3 +1,3 @@
-| EmptyJWTSecret.rb:9:21:9:34 | call to [] | This JWT encoding uses empty key or none algorithm. |
-| EmptyJWTSecret.rb:12:21:12:34 | call to [] | This JWT encoding uses empty key or none algorithm. |
-| MissingJWTVerification.rb:6:38:6:44 | payload | This JWT encoding uses empty key or none algorithm. |
+| EmptyJWTSecret.rb:9:21:9:34 | call to [] | This JWT encoding uses an empty key or none algorithm. |
+| EmptyJWTSecret.rb:12:21:12:34 | call to [] | This JWT encoding uses an empty key or none algorithm. |
+| MissingJWTVerification.rb:6:38:6:44 | payload | This JWT encoding uses an empty key or none algorithm. |